@trentor only seeing this now. Were you able to fix it?
I gave up, have too much other things to do On my old laptop, where this has happened too, I simply disabled the lock screen and just use root when I would otherwise have used sudo. Not ideal, but better than wasting more time trying to fix it. On my new laptop, I just installed Ubuntu instead for now, which is working without issue.
I will probably try a clean install on my old laptop in the near future and see if it persists and if its fixed, I’ll try the same on the new laptop. But probably not for a few weeks.
I have the same problem and still unable to find any solution. I run Manjaro since 2011 and would be sad to give it up because of this. Fortunately I don’t need my computer for anything serious right now so I can live with it, but it is a very strange bug.
I did a clean install right after I got it but still came back with an update.
I finally have found a workaround.
The situation is that something in the background (haven’t found what exactly) expires my password retry count and locks me out. Not just sudo is waht is affected, if I do a logoff and try to log back on, my password is not accepted.
The only way I could work around this is to set the retry count to zero in /etc/security/faillock.conf (deny = 0).
I know this is a potential security risk and I need to find the real solution (eliminating the background login attempts), but after almost a year, I don’t have to reboot to do anything that requires authentication. Interestingly pacman still works with the root user, just my regular user is affected. Very strange.
On my old laptop, where this has happened too, I simply disabled the lock screen and just use root when I would otherwise have used sudo. Not ideal, but better than wasting more time trying to fix it. On my new laptop, I just installed Ubuntu instead for now, which is working without issue.