28 minutes of 1080p on a cell phone? What the heck are making videos of lol.
In all seriousness, what is the file size of the video? If its roughly ~4GB, that might be because the FAT32 file system doesn't support files larger than 4 GB. But the Nexus doesn't use FAT32 anymore for the /sdcard/ partition, so it might be something in the camera app that is limiting it on purpose for backwards compatibility for phones that still use FAT32 for the SD card. In other words, there may not be a whole lot you can do other than starting and stopping the video very quickly at the end of that time.
But that's a complete guess, because I'm not willing to make a 28 minute video to test that out, so it may be something else.