I think I found a bug in special conditions:
2 layers with VHS each
in code: disable all VHS (button: enable VHS -> wait x seconds -> disable VHS)
BUG: Sometimes (every few seconds after disable it) the top layer change the width of all objects for 1 frame and back it to normal size.
Not always happen, and the time is random.
If you test it with 3 layers, this happen to layers 2 and 3, but never to low layer.
Solution: Don't disable this effect. Set all VHS parameters to 0