Screenshots? Result clip?
Image 1 uses layer effect Gradient, this is a saved image using the normal Save as jpg.
In image 2 this effect shows up, but wrong, in the exported image (export video as jpg). Also note the pencil tip gradient effect missing, which naturally is a separate layer. All parts are vector shape layers.
This bug might only apply to gradients, but I haven't checked all other layer effects and results (something Adobe should do).
The file contains 50 frames and roughly as many groups with layers and effects.
Works for me, at least on a quick test using a simple file. Perhaps you had accidentally multiple frames/ layers selected and tweaked something and thus intruduced some temporal incoherence. That may also explain your otehr issue with layers repositioning...
Thanks for spending time on the simple test.
Anything is possible. I doubt a bug can be "accidental". It's an actual problem and I have produced examples above.
Whether it is important enough to investigate and fix is another matter.
This happens to many of the files I have that use multiple layers, effects, groups and frames.
If you really have an interest infinding and destroying this bug I suggest you create a file with 50 frames, 50 groups with multiple layers with layer effects turned on/off between the frames, tosee if you can replicate it, since a much simpler, smaller file doesn't seem to reproduce it.
I realize that if this has only happened to me this bug won't receive any attention and I'll have to learn to live with it. But at least it's now reported and if others have similar problems they should be able to add to this discussion.
A shame the "normal" bug reporting tool through Photoshop.com is disabled. Chances of them finding this bug here is slim. But you found it