There are multiple softlock cases. Other than that:
1) If you kill or eliminate Riliane in some other way - after getting the slimes crystal the game softlocks if you go through the left door, but everything works just fine if you go through the right one.
2) The whole Arowar situation is super sensitive to the sequence breaking. If for some reason you kill the guards BEFORE getting the slimes crystal - the dialogue option to start the war doesn't appear anymore when you talk to Gaia.
3) And my favourite bug is being able to recruit Scheherazade semi-permanently. How? After killing the Arowar's guards she won't leave the party before getting into the village. It's super helpful for any difficulties harder than easy, but there's one issue: for some reason she appears in the begginning of the Arowar's war where you put the wisp on the map. If you select her - the game crashes.