This behavior has been introduced in 0.22.1.

Steps to reproduce:
1) create a list item with some text
2) put cursor at the end of the text
3) press Enter
Expected: it should create a new list item
Actual: it creates a new paragraph within the same list item
If that's expected, then it is a breaking change since 0.21.0 and should be documented I think.
It's more natural behaviour that when I hit enter, it would start a new list item. Google doc and dropbox paper are doing the same.
Definitely not expected. I'll look into it later.
like I said before, one way to fix that would be to make the following change inside canSplit method
let after = (typesAfter && typesAfter[i]) || node
That was indeed the problem, fixed in attached patch and released as prosemirror-transform 0.22.2
Oh, I meant this patch
Most helpful comment
Definitely not expected. I'll look into it later.