My two cents on the same ordeal.
Firstly, I'd like to say that all in all the S60 is a wonderfully built and eye pleasing bit of kit.
The thermal camera might be a niche gadget, and the device itself caters to a specific breed of users,
but it is more than well suited for me and my approach to work in the field - the main benefit being
the fact that I always have a thermal camera in a nigh-indestructible package right in my pocket. Plus, this
particular camera doubles as a smartphone!
I work in industrial electronics applications (including automotive and heating applications, furnaces etc.) with a
recent shift toward R&D (PCB development and product design). For finding which hydraulic valve is which on the principle
of activating it and watching what solendoid starts to glow makes this phone a godsend. Also, imagine working with many
different commercial vehicles and finding the correct relay or power line without any schematics...
I have used Galaxy S3's and S4's in the past, beated them mercilessly and exposed them to conditions Samsung hadn't
really intended them to be exposed to. A rubber bumper case seemed to protect them from all the falls (including 2m+) somehow,
and an S4 even took a swim and survived it.
As with all previous non-smart-phones, I just wouldn't let them die as long as there was some bit of
them I could replace with parts of scraped phones or re-work burnt electrical connections in their inards.
All that being said, please note that I don't have sadistic tendencies or take joy in inflicting pain to phones, I'm very
observant with them - I just work in all-round hostile and dirty environments so my equipment and I do accumulate scars
as we go along.
I have been waiting for the S60 to become available since it was announced and of course I got one
as soon as my carrier started to offer them for a nifty price of 24 payments of 22 EUR per month.
I figured this is the phone to go with. Water- and bomb-proof, the thermal camera, sleek design, what could go wrong?
I'm not partial to Apple, Samsung or any other "big name" brands but I've always been sceptical of CAT phones, mainly
because Bullit isn't really a time-proven maker of smartphones.
Not everything about a phone is it's shell and the hardware-software paradigm that Android phones are built around.
For some of us, it's the little things - imagine a phone that's sealed and built like a tank, but has software issues
(crashes, reboots) or minor hardware issues because somebody in R&D just didn't test thoroughly - like people not hearing
you clearly, you not hearing them clearly, service unavailability where other phones manage to get through... these are the
things that can drive a user like me insane and deter me from purchashing such devices. Guess what, these are all issues that
I've seen highlighted by ruggedized phone users (this doesn't fly directly toward Bullit/CAT, but you see where I'm getting
at).
Now imagine boasting an ingress protection rating of IP68 and exceeded military specifications for drop resistance. Us
working in industrial applications get this immaculate and pragmatic picture of other equipment in our minds, and for the
most part, the S60 is exactly that.
But... the flap at the back that covers the SIMs and SD cards? Come on, this is a tremendusly weak spot in otherwise such
a spotless-seeming design. I'm not a fan of the hinged USB and earphone covers either, but at least they got them right.
But this thing at the back has "Achilles' heel" written all over it. Sure it does protect the inside of the phone from water
but think about it - this is a phone for people who own screwdrivers - couldn't you have just put some screws to firmly hold
the backside of the phone together? And a nice, big O-ring around it all? Like it's always been done?
I mean, it does work good once the phone is new, but the rear door does travel somewhat in all directions. What will happen
in time? What will happen when that gasket sits on dust instead almost-mirror-polished plastic? Or once that yellow stopper
holding the door becomes worn?
Okay, granted, in my case it wasn't even water ingress that got the phone (or was it?). I just wanted to see if
the two holes at the back on either side of the FLIR chevrons correlate to the "Show waterproof warning message" (they don't)
and dunked the phone into a glass of cold water.
Upon drying the phone with a towel I opened the back door to inspect it's waterproofing capabilities (bear in mind that the phone
was less-than-CAT-logo deep in water. The door did it's job.
Sure enough though, within minutes, the camera window begun to fog up - an omen of the things to come.
A night spent burried in Silica gel seemed to get the moisture out of the phone, but once checking all the functionality I found the
same symptoms as noted in OP's post. The thermal camera would wash out the colors within 10 or 20 seconds, indicating that it could not
distinguish between temperatures anymore. A ghostly afterpicture lingered as I panned the phone around. The temperature readings rose to over
45°C even though I'm fairly sure I don't live in a Taiwannese sweatshop.
Seeing how my carrier doesn't take kindly to water ingress in any phone (IP68 certified or not) warranty-wise, I knew that my
only alternative to a costly repair was sorting the damage out by myself.
Luckily it wasn't difficult to figure out what was happening.
See, the Lepton sensor (the CCD equivalent in the thermal camera) has a built-in mechanical shutter (the size of which probably
adds to the size of the bulge on the top of the phone - I find that bulge marvelously streamlined into the phone's design, by the way).
The shutter is closed periodically, allowing the thermal camera to take an unadulterated dark image as to calibrate itself. You can hear it
clicking if you listen closely. The FLIR app freezes for a moment while it self-calibrates (it's a feature, not a bug!).
Mine wasn't clicking. Instead, quite rapidly, the housing around the thermal camera window begun to heat up (resulting in the faulty
temperature reading). Once left alone the camera gradually cooled down. If only I had a second thermal camera-phone I would make a badass
time-lapse gif to show you.
My guess is that the moisture in the phone glued the leaf of the shutter to the housing. As it is probably magnetically actuated, the mini
solenoid inside the mechanism heated up because it had nowhere to go.
Remembering my experience in percussive maintenance I hit the phone sharply on the table in the interval when the shutter was supposed to
close and successfully dislodged it.
Works fine now.
Whether the phone already had moisture inside when shipped and it condensed because of the cold water, or whether I let the moisture in
by opening the rear door (this was in a kitchen after cooking, so I guess there could have been more humidity in the air) I leave for
academic debate.
I waited for some bad user experience on the web before getting this phone, but got it early anyway because there was no really negative
reviews to be found. It is a great device after all. Everything has its shortcomings and I really hope these kind of mishaps don't
blemish CAT's (Bullit's) image in the smartphone market. The fact is that CAT managed to get my attention with this phone and they
will get more attention because of it.
I will, however, laser cut a piece of duct tape to fit snugly over the rear panel before more under water encounters. Duct tape always comes
in handy after all.
Solenoid valves
Automotive relays
Overloaded wire
Hornet sting
Circuitry and power cable
) i saw that phone was powered off (!!!). Restarting it, i saw that immediately entered again in restart loop. Checking closer, i saw some condensed water inside(!) the camera glass. 
