When an edit is pending on a post, further edits are not allowed. Clicking "edit" brings up the edit review instead of the post editor. This flow makes sense.
However, when an edit is pending on a post, you can still rollback to previous revisions, which counts as an edit. You can do this by viewing the edit history of the post (if there is any) and clicking "rollback". This all, of course, assumes you have enough rep to edit posts.
I think this is a bug: Not allowing edits while another edit is pending review makes sense, and the fact that rollback edits are still allowed seems like an oversight. Rollbacks should not be allowed if other edits are also not allowed. Either that, or all edits should be allowed when an edit is pending. Either way, consistency.
Also I noticed that applying a rollback does not seem to cancel any existing pending edit.
I do not actually know what happens if you apply a rollback while another edit is pending, and that edit ends up approved, and there is a conflict.
