Board Thread:The Quarters - Q & A/@comment-49.147.162.17-20160405015559/@comment-24672610-20160405023259

There isn't a limit to how much damage you can do per day. All tasks you complete should be damaging your boss! However, you only deal damage once per day. It sounds like maybe your Cron ran after you had done some tasks, then you later completed others that you considered part of the same day, but they were after midnight (or your Custom Day Start time if you have one). If that's the case, you will do damage for the later set of tasks, but that won't take effect until your next cron.

If that doesn't sound right, the other possibility is that you ran into a Sync Error where the server wasn't able to register the fact that you completed the later tasks. If that's the case, you also wouldn't have gotten other rewards (e.g. GP and XP) for them, and it would otherwise look like they weren't completed (e.g. Dailies would have their streaks reset, To-Dos would go back to being not completed). That's unfortunate if that happened, but you can read about how to help prevent that kind of error in future at the link.