Still on user pages slash is substituted in the canonical. (jm_canonical_1.4.4)
P.S. The news is working well.
That url is related, so it's already generated with slash.
In fact this is correct (no 404 with or without slash). I could add prefs for this and customize generating. (I want that slash :) and you don't want it, so prefs).
Check mainly pagination. With forum. It somehow changed between 2.1.8 and 2.2.0.