You’re not the only one.
Now after nearly two years, my FP2 also behaves similarly.
I have already in my FP2 life:
- replaced the first case by the thin case because the volume buttons were losing their shape
- switched the camera and power on buttons of this second case to avoid reboots
- added some tape to maintain firmly the battery in place to avoid reboots
- changed the bottom module because the USB connector and microphone were out of order
- changed the rear camera (just to enjoy the enhanced photo capability
) - changed the screen because it started to display coloured pixels and other strange beahviour like the photos you posted and disassembling/cleaning/letting it dry in case it was due to droplets did not change anything
Now this display issue is really exhausting : everything is OK and suddenly it starts again, I am forced to twist my phone to see if it makes things better. Sometimes the FP2 displays a messages stating that the app that was running (whichever the app) is not responding, and the screen being unresponsive, only a battery removal can help.
I now dissassemble my FP2 on a daily basis, and each day I feel my patience slowly running low 
Note that I consider the hard reset as a really last chance solution, but I will have to find some time to backup and restore my apps and configuration.
Sevan
Some links to screen issues: