It appears the biters view the maze terrain as path able, AS large hoards of them seem to be gathering at the shortest line of sight to our base. However these are blocked by maze chasm tiles. As theoretically everythings working as intended (but not) I have no crash logs to give you only my word.
In terms of mods we are using the most up to date rampant so Will probably remove that and see where we go from there for now.
