The stone statue bunch in RPY level caused an internal error
"You change position with the stone statue. *** An internal error has occurred. Stacking monsters (a stone statue/281 {0, 16641} [46,10] with a stone golem/55 [46,11]) at (46, 11) is not allowed (L:11, 5; LI: 115). *** I'm trying to fix this by simply deleting the stone statue."
Game managed to continue. Precisely before this happened, the
"A stone golem grows out of the ground and takes its position as a silent guard."
Seems to be occurring when a stone golem gets generated on your square and you are not able to move away from the square immediately the turn afterwards. Maybe the generation happens one turn too early?
Damn, the fix for the last version (same problem) again was broken but apparently I tested it on the one single space on the map where it worked :-( Damn, damn, damn...