HTML list grouping broken after 2.7 update

After updating from 2.6 to 2.7, grouping into a HTML list produces the groups but the entries are not in their respective groups (the number of entries per group is correct, but the entries are in the wrong groups). Grouping a table produces the correct results.

Might have something to do with sorting, when I also enable sorting by node title, and group into a HTML list, the number of entries per group is again correct but the entries just continue in alphabetical order, irrespective of groups.

Attaching two screenshots, comparing HTML list grouping vs. table grouping, notice the entries are different.