I encountered a similar problem.
The pattern I found was that when I pulled the Inspectors window to about 1/3 or so (Full screen), when the computer entered sleep mode or enter the screen saver (It needs some time, not immediately) and then activated the computer, it would appear
System：
- Mac mini M4 24G RAM macOS 26
- MacBook Air M2 16G RAM macOS 26
- DEVONthink 4.1.1