Well, downgrading to 4.3.1 stopped the flood of error messages! Now the question is “what caused the newer version to start throwing errors?” I don’t know, but I hope someone can figure it out! I checked out CronArchive.php on Github, and the only thing that seems to have changed between versions is the removal of “Common::” from the file. But I have no idea whether that’s relevant to my problem or not.