May 20, 2023
Volcanoes don't erupt in Dwarf Fortress. Except when they do.
introducing:
Bug 0008183: Overflowing magma seas/pools after unretire or reclaim.
unretired a fort, I discovered a magma sea (without message, just saw that it is there). The top layer of magma changed it depth constantly ranging from 5-7 after some time it would overflow and flood everything arround it. It doesn't stop.
This overflowing of magma seems to be triggered when walls are built around the rim of the volcano causing issues with calculating the height of the magma.
Eventually, you get this end screen as the map is flooded with magma:
Your settlement has crumbled to its end.