The copper golem can only put items into a chest if the chest is empty or already has the item.
I did try that and same issue. It worked once and only once when I disabled all of my computer’s non-Microsoft processes so I think another app is blocking Minecraft somehow. Probably Unity.
The error continues to occur even after redownloading the Minecraft Launcher
Here’s a video, since I couldn’t seem to add it to the bug report itself
They appear to be changing to random other textures in the texture map, for example brown banners seem to show clock and flowing water textures