I'm pretty sure your theory is correct. You can query the list of interfaces with pfctl -vsI, which prints '(skip)' on those that are currently being skipped.
Reloading the ruleset does (and should) clear the 'set skip' set, as we agreed that there should be no (or as little as possible) state in the kernel that persists across ruleset reloads. Other options are similarly cleared on reload (and then re-instated, if you reload a ruleset similar to the old one). So loading an empty ruleset should clear all such options. Now, if the ruleset doesn't exist at all (I assume you didn't have a file called 'all' lying in the cwd when running pfctl -f all), I guess nothing should happen except for the error message. I'll check about that. Or what would you prefer instead? Daniel
