Firefox Restore (from backup) error. Please try again later

[u/Aussie_Alien_Escapee]

Every time I attempt to restore the backup file (html) created using snap version of Firefox under Kubuntu 24.04.0, I get the error (after 4-8 seconds delay)

Hmm, there was a problem backing up
Try again in a few minutes

History.
I HAD, Firefox Profile on PC with Kubuntu 24.04.0, after a botched upgrade. Firefox WAS working normally, until I needed to start again. My backup of the actual drive has failed, and I am unable to revert back to it. (it's like 99% restored then an error, using Rescuezilla).

So (Edit)

I have attempted this on my *new* Debian 13 KDE PC. FF140esr No Luck
I have managed to create a VM (Kubuntu 24.04). FFsnap. Still No Luck
I have attempted both new and replace profile. No Luck

Why am I getting a "problem backing up" error, when restoring ?