Exp. Player V11.14.19:C474AF8
The update of for some reason messes up the position of the pre-placed lemmings. See below for an example: in Breezy 3, all the lemmings should be blockers in the old version, but after the conversion, the pre-placed lemmings are walking. I didn't even use any walkers on them.
Also, in the editor, it is shown that the pre-placed lemmings are buried within the terrain.