Playing the Orcs campaign I went to the Dominion port, in the sewers I entered a hidden vault, when I exited the vault and went back to the sewer the game got stuck with a "Generating level" loading bar, even if the level is the one I came from.
This is what I found in the terminal:
Lua Error: /engine/Zone.lua:934: requested zone generator of type map but it is not defined
At [C]:-1
At [C]:-1 assert
At /engine/Zone.lua:934 getGenerator
At /engine/Zone.lua:1001 newLevel
At /engine/Zone.lua:918 getLevel
At /mod/class/Game.lua:1036 changeLevelReal
At /mod/class/Game.lua:841 unload
At /engine/Game.lua:430 unregisterDialog
At /mod/dialogs/ShowEquipInven.lua:179
At /engine/KeyBind.lua:264 triggerVirtual
At /engine/ui/Dialog.lua:483 fct
At /engine/Mouse.lua:58
I did a backup of my .t-engine, in case you needed it to test. It happens every time.