States count in firewall rules

[darcey]

Looking at the states/traffic column in firewall rules, I have at least one rule that reports zero states and that, when I click through to the states table, shows a matching state.

The example I'm looking at at the moment is SIP traffic, which sends a keep-alive every couple of minutes. I have the firewall optimization set to conservative.

Why might the rules page not reflect the matching states count?