Recently did a new install of Linux Mint 22.2 (Zara) and was annoyed by getting prompted for authorization (Alternating between prompting for 'Authentication is required to update information about software' and 'Authentication required to modify a system repository'.) every time it checked for software updates.

Turns out that out of the box, something is broken with the Flatpak setup.

Pretty easy to fix, once I did some research:

flatpak repair then sudo flatpak repair

Worst case, you get into the Software Updater's Preferences and turn off “Check for Flatpack updates”. (Then just be sure and occasionally run flatpak update from the command line to check for/install any flatpak updates)