I had the same thought, so I actually created some new tag without special symbol like "aa to be managed soon 4" as shown as in above screenshot, and it is having problem, so I temporarily ruled out this part of thoughts.
I picked 3 outstanding error messages occurred during the last 24 hours or so as shown as below:
2024-03-04 18:44:54: Synchronizer: "Error: Cannot acquire sync lock: either the lock could be written but not read back. Or it was expired before it was read again.
Error: Cannot acquire sync lock: either the lock could be written but not read back. Or it was expired before it was read again.2024-03-04 18:44:56: Synchronizer: "There was some errors:"
2024-03-06 14:03:06: PluginService: "Could not load plugin: C:/Users/yangk/.config/joplin-desktop/plugins/io.github.jackgruber.backup.jpl", "Error: Plugin was not started due to safe mode: io.github.jackgruber.backup
Error: Plugin was not started due to safe mode: io.github.jackgruber.backup
Beyond the last 24 hours, there was another error which were discussed in this forum and considered fixed (maybe), but the tag problem we are talking about for the time being was not related to this back then, the message is as below:
2024-03-04 15:16:04: shouldPasteResources: "Pasted text:", "Follow up "Joplin fatal error "Unknown profile version" - 2024/03/03"."