I don't know how many times I've been bitten by this. Typically I want to approve a PR "from my perspective", but still saying that the author needs more reviewers. So I go to the Files tab, fill in a comment like:

Build changes ok.
/reviewers 2

and press approve.

And the command is just ignored by Skara. :(

I guess the same goes if you would make a single comment in review mode as well, but I have not tested this.