What possible explanation could there be that Bitcoin Core on Linux Mint claims to but does not save the wallet backups?

[Bitcoin]

What possible explanation could there be that Bitcoin Core on Linux Mint claims to but does not save the wallet backups?

Linux Mint. Bitcoin Core 0.21.0.

I go to "File" and "Backup wallet", then select any location. I've tried with /home/a and /tmp and others.

Every time, Bitcoin Core says that the file has been successfully saved to the location I picked.

Then I look at that location in the GUI file manager, as well as in the terminal. THE WALLET .DAT BACKUP FILES ARE JUST NOT THERE!

I swear I'm not making this up and that I've enabled "Show hidden files" and tried everything to make sure that I'm not doing something wrong.

The files just are not saved, even though Bitcoin Core claims that they are. Why?

They are just not there on my file system. The only wallet.dat that exists is the actual one that Bitcoin Core itself saved, and it has put that in: /home/a/.var/app/org.bitcoincore.bitcoin-qt/data/blablabla/wallet.dat

At this point, having tried and asked and searched so much, I'm starting to truly question my sanity as well as the QA of Linux/Bitcoin Core.

This is even worse than various file nonsense in Windows. Is there some secret, very well hidden setting that I need to enable to "actually show the files" or something? Beyond "Show hidden files"?

Source: What possible explanation could there be that Bitcoin Core on Linux Mint claims to but does not save the wallet backups?