If you open one quest with a custom subscreen then opend another and tried to add a tileblock to it's subscreen some parts of the last quests subscreen will be put on the current. (Haven't tried anything else.)
Overlaying Subscreens? (12c)
I have seen a variation of this too. I edited one subscreen, opened up a new blank one.. and the old subscreen was there!
This seems to be fixed, I played with this quite a bit yesterday and couldn't get it to happen.
Anyone confirm otherwise?