It is probably all the google telemetry and monitoring and wifi scanning to map your location for sale that is running in the background. I plan on getting a pixel 7a soon but will immediately wipe the google junk and load grapheneos. Apart from getting rid of all the spyware this also doubles the battery run times.
I wouldn’t trust a google phone telling you that a competitors browser is problematic
Hand sanitizer is all French wine is good for anyway.
When I worked for a telco in the 80s they had a nightly script for two backups over three tapes. The script asked the operators first for tape 1 then tape 2. Started the second backup which asked for tape 1 again. This overwrote the first backup. Tape 3 was never used. I found that problem before they ever needed a restore.
Maybe you unplugged the device before unmounting it leaving the filesystem in an odd state? Next time it fails to auto mount check /var/log/syslog for recent error clues.