Was this always the case or is this supposed to be this way after the last update? I checked a heal parse tonight and it was critting 4% of 103 hits. Doesn't seem right since it's not a proc.
That figures. As a sanity check, I went looking for a Templar parse to see what Involuntary Cure (now Gift) was doing. To me, this spell amounts to roughly the same idea. Turns out it crits just fine, meh.