Yeah, I finally noticed that in the process of trying (unsuccessfully, as you might've read by now) to do Tricky 23.
The Amiga version also happens to have the same sort of mask for the basher incidentally.
Although, I observe something even stranger, possibly related to the lumpiness of the back end: A0;try doing a sort of "backstroke" against the wall and see what gets removed. A0;(It might sound crazy, but it actually looks to me like you need to assign the basher a split second before the lemming actually turned around against the wall......) A0;I don't think I've seen that at all in Amiga version, despite the lumpy back end being in that version also.