List.Map not behaving. List count mismatch?

So I’ve got one that I can’t get my head wrapped around: I’m using List.Map to apply a BiMorph node to collect clashes. Seems simple enough, and I’ve used similar graphs successfully in the past. I have 200 items in the input list, but I’m only getting 199 items in the output list. I’ve never had this happen.

List map with item counts