Topic pretty much says it all. As soon as I disable ATT it all gets back to normal. Not sure what i need to provide here to hel you pinpoint the culprit.

Also getting this problem, and disabling all things seemingly related to quest tracking doesn't resolve it.

I don't care to track quests; only rewards I haven't obtained that might happen to be related to a quest - but I suspect that is tracked without needing to look at the quest itself. The stutter is a minor nuisance, but over time it becomes pretty aggravating and makes me not want to use ATT.

Still happening. Tried to randomly disable one settings after another, nothing helps. Seems to be core functionality that's causing it. Any way we can help debugging it?

Does this stutter still happen in the latest version of ATT? (2.1.4) There have been some underlying modifications that have been made since this issue was opened, and I would like to know that things are still causing problems before spending time looking into what might be the cause.

It's gone now! Quest completion happens smoothly.

Going to close this since the original cause has hopefully been addressed at some point. Any new lag/stuttering determined can go into a new issue.