There's an oddity with the "Difficult" staircase in Mother Lode, the last battle of The White Star. Pokkin (or you) can just go around the corners and ignore the terrain. This might be intended, but it was treated as something to fix the last time I mentioned this sort of thing, so I bring it up now.
I had an issue last night with some tiles appearing with upside down exclamation points on them and the message "OPEN Costs one move point to enter. Doesn't block sight." when I right clicked them. They appeared randomly on several maps and only seemed to affect normal "open" terrain squared. They didn't appear on every map, but consistently throughout my play session and usually at least one map per module. So far today I have not had them appear. I didn't think to grab a screenshot of them.
I'll give it a go, i'll try and corall another enemy into that corner (and take the entire log if I succeed).
Here is an example from the War monkeys scenario. You can see the monkey (barely) on the victory tile. My elf had died the previous turn. Perhaps the monkey is... irrepressible!
All overturned stools are Difficult terrain in Scenario=Lizard Feast Hall, Room=SLUB. But in Scenario=Prison Warden, Room=RESC, RoomID=83955 the overturned stool and wine rack are Open terrain.
On Frozen Bridge (BTFE), trying to see past Impassable terrain limited my Dash to 2 spaces (when trying to move diagonally around it).
I lost it, sorry. I was thinking about what happened, though, and I think it's probably because there was an enemy adjacent to my destination. There's a mechanic where terrain next to enemies becomes Difficult, right? Because that would do it.
Scenario=Arena Battle 1-3,Room=ARN0 Last battle of arena qualifiers, some of the walls near victory squares are missing black outlines. Also, module cover doesn't say how many battles there are.
Looks like a missing doodad. Either they changed something - or you're not loading properly (seems to happen on rare occasions). Either way, it's an ok place to post it I'd say - if you want to make sure it's a permanent error - close the client and restart to see if there's any change.
Sorry, I don't have a screenshot, but: When fighting a large enemy (one of the Ogres in High Mountain Pass), I used terrain effects to get it where the Ogre was standing on one Lava square and one Acid square. He took 10 from the lava, but was unaffected by the Acid.