This is a weird one.
I went on a trip recently, starting on April 17. Before I left home, I shut down and unplugged two desktop PCs, and took two laptops with me on my trip. All four of these machines are running Duplicacy, installed for all users (using the service) and set up to perform scheduled backups.
Since I returned on April 28, the two laptops that I took with me are backing up according to their schedules, but the two desktop PCs, despite being powered on, connected to the Internet, and working otherwise normally, have performed no backups. (I determined this by checking in the .duplicacy/logs folders and seeing no logs after April 17.) I have checked to make sure the Duplicacy service is running (it is), and the GUI is set up to perform the scheduled backups (schedule box is checked, and green dots exist in all the job tabs).
Yet, no backups are happening.