Help Emails suddenly full of equal (=) signs! Sony Xperia Aqua

[bigblueamazon]

Hi, I'm using a Sony Xperia Aqua and for no apparent reason all my incoming emails are suddenly peppered with random '=' signs all over the place. When I download the same emails on my laptop the = signs aren't there in the incoming emails, so it's all a bit strange.

Please does someone know how to fix this?
Grateful for any help offered.
Thank you.