I ran into this when answering a
question about nesting sets of multiple powers which I suspect is actually addressing 3E, but I found the bug in 2E.
As you can see in the attached picture, the base Alternate Form at 4 ranks costs 20 pp. The nested Alternate Form at Rank 4 costs... 1 pp?
I think that what's happening is that, at some level, it's considering that Alternate Form to be a 1 pp AP, or possibly assigning it a cost of 0, coming out to 1 pp due to the rules saying everything has to cost at least 1 pp.