DEBUG : completed mission 26 was not in the active_missions list

### Describe the bug

DEBUG : completed mission 26 was not in the active_missions list

FUNCTION : void avatar::on_mission_finished(mission&)
FILE : src/avatar.cpp
LINE : 355
VERSION : 6f0e11a

### Steps to reproduce

I was just walking around.

### Expected behavior

?

### Screenshots

_No response_

### Versions and configuration

Linux
Experimental build 2022-11-10-1351 6f0e11a
tiles
english
dda, no_fungal_growth, alt_map_key

### Additional context

_No response_

Start in src/avatar.cpp at avatar::on_mission_finished, around line 355, and inspect how completed missions are checked against active_missions. Reproduce the debug message if possible and determine the expected behavior for a completed mission that is not listed there; the issue does not define that behavior or provide a reliable reproduction.

Written by the indexing model from the issue text.