"Update Firefox" bug in TBB
I was running the latest TBB (6.0.3) and launched it but I was getting an error that "Firefox needs an update", which didn't make sense since Firefox is not running, the TBB fork of Firefox was. I checked the "Check for Tor Broswer Update" but it was not returning anything. I then re-downloading 6.0.3 and re-checked GPG keys (valid signatures) but was no longer seeing this pop-op.
Out of an abundance of caution, I took pcaps during the time of the popup and I noticed all the traffic was properly routed to nodes in the Tor network. I clicked the button and it routed me to the Tor Project webpage (no SSL warnings). I can provide pcaps if needed but @mrphs says it might be a simple bug in the updater.