A Lesson to Learn still shows up as available on the map and minimap after accepting it.

https://classic.wowhead.com/quest=27/a-lesson-to-learn

4.0.18

Did you try to reload Questie? Crtl + leftclick on the minimap icon.
Sounds like either the desync bug or a really bad database error. Will look into this later

I found out what's going on, y'all mixed up the Alliance and Horde sides of the quests. In your database, quest n°26 is the Horde side, but what I actually completed with my Tauren was quest n°27.

Gonna do the rest of the questline to see what's what.

Thanks for investigating the issue 👍 I will have a look at our data very soon and if you're right it will be an easy fix!

So 26 and 29 are Alliance, while 27 and 28 are Horde. The rest of the line will take a bit more time, sorry.

Finished the questline, everything else is fine and dandy. The only mistake is with A Lesson to Learn.

Thanks for your very detailed report. This is fixed now!