Yes, sure. I just wanna try in various way.
I didn't find this issue on PC in preview but frame per second detected 60 in debug mode. It should be 30 fps because I set max delta-time is 1/30. Maybe I misinterpreted it.
Does it still happen if you touch the mobile screen from time to time?
I test this. it's still become jerky after around 2 minutes.
I tried your method, it looks ok. The moving image still normal after 5 minutes.
TiledBackground: Set image X offset to (Self.ImageOffsetX-60×dt)%Self.ImageWidth
Great thanks.