Hello Diplocaulus,
Welcome to Microsoft Community.
According to your description, this situation started about a month ago, right? That means that at least initially, the File Explorer doesn't have this problem, right?
Can you recall any operations you performed on the device when this problem occurred? For example, what applications are installed? Has the system been updated? Or have you changed any Settings? It's important to remember as much as you can, because it's likely that this question has something to do with it.
If you can recall any changes you made or any programs you installed, try to undo the changes and uninstall the corresponding programs. But if you really can't remember anything, please follow my instructions.
Please perform a clean boot on your device first. By performing a clean boot, this is a mode of disabling third-party services or software, which could help rule out the interference of these elements.
Disclaimer: A “clean boot” starts Windows with a minimal set of drivers and startup programs. It helps to determine whether a background program is interfering with your game or program and to isolate the cause of a problem.
After a clean boot, please search for "CMD" in the taskbar and open Command Prompt as an administrator. Type the following two commands respectively, and press Enter to execute the command:
sfc /scannow
DISM /Online /Cleanup-Image /RestoreHealth
These two commands are used to repair the system. After executing them, please restart your device and confirm whether the problem still exists in the File Explorer. If the problem still exists, I will provide you with some complicated repair solutions.
If anything is unclear, please do not hesitate to let me know.
Best regards,
Mitchell - | Microsoft community support expert from MSFT