This might not lead to much but on a hunch, I would be keen to look into the battery usage on your phone? It might be that your phone keeps going in to powersave mode and closing apps if it believes their is an exessive battery drain...

Could you check that powersave of off in... Settings > Device > Battery >Power save: OFF

This menu will also give you the Battery condition status too.

Then if it is possible (I understand this may take some time), download the Battery Monitor tool from ovi and check the Average consumption.

It may be that you have a dud battery or it can be another thing to rule out?


Edit: Thanks for replying to my post mate, I was first thinking that there maybe a screen fault. Mine shows similar symptoms to my post.