If you track the jewelcrafting quest called Gem Perfection in Borean Tundra Valiance Keep, the Questie tracker vanishes from the display and stops working.

This bug can be reproduced in the following way.

1. Pick up the quest.
2. Go in questie setting disable auto tracking.
3. Reload ui.
4. Open quest log and try to track the quest using shift click.
5. Questie tracker stops working.

For a better visual appearance of the bug its good to have some other quests in the log and start tracking those. Those will work and just as you start to track the jc one it stops working.

Questie version: V7.2.1
Wow version: Classic Wotlk

Thanks for the report. As you mentioned, a temporary fix is to Untrack/abandon the Jewelcrafting quest "Gem Perfection" for now. We're working on a fix.