Envelope distort shapes result in different results

[nmycps]

The first image shows pinched rectangles as the object to distort the text to. The left one has two additional nodes, the right does not. After applying the E.D. effect, big difference in results.  Is this a feature bug or is it normal for this to happen? It doesn't seem to make sense.
Thanks for any replies.

[Doug A Roberts · Accepted solution]

Some types of shape with zero-length handles result in an envelope consisting of a mess of overlapping paths, and it is a bug of some sort:

https://illustrator.uservoice.com/forums/601447-illustrator-desktop-bugs/suggestions/43013964-envelo...

[Monika Gause]

You can achieve that envelope with the default "Bulge" envelope. Just set it to negative values.