Without knowledge of what you layer content are we can not tell if the thumbnails are correct or not correct. We have not idea how you have the Palette's panel options set. Many of your layer contain lots of transparency. When most or a layer bounds are empty of content you can not expect much from] the Layers Palette layer thumbnails. I also have the thumbnail set to entire document so I have a idea where layer content fit within the documents composite. You seem to use Layers bounds and content within your layers bounds seem sparse. The checkerboard in the first three layers are larger thee the ones in other thumb. The also look soft like they may be screen captures the have been resized. May actually be gray and white pixels not empty. It would have been helpful it the turned on the visibility of layers and included the composite image in your capture
thanks for your answer. I use the smallest thumbnail size and have activated Layer Bounds. The other settings are the same as in your picture. I work with many layers with cut-out objects on them. Actually, in my example (layer 29, layer 20 copy, layer 20) should show something similar to layer 8. The error only occurs after a certain time.
You can recognize the error by the fact that the grid in the thumbnail in layer 29, layer 20 copy and layer 20 is larger than in layer 8.
The "Layer Bounds" function is very important to me, so that I can quickly see what is on which layer.
Can you describe how to produce this problem or save the document that has this problem as a PSD and when the saved PSD is opened in Photoshop the open document has the issue. I do not use 2021 it has issues Adobe need to Address IMO. When I tested 2021 I did not notice a problem like your's.
The problem only occurs when I work longer in the document. It occurs on all of my documents. I suspected I was running out of memory, but I think 16 GB should be enough. My documents are around 200MB in size.
I will continue to watch this to find out from what point in time the problem arises. And I'll test it in an earlier version.