pfSense

It isn't random, it's just using what it knew at the time.

The rules are matched using what is recorded in the actual pf log by pf when processing the traffic. If the rules were reloaded/changed in between log messages, then it doesn't have a way to know what rule processed that traffic at the time the rules were different, so it prints the description of the current rule using the number instead.

At the time the log message didn't line up, something else must have inserted a couple rules and then took them back out.