Went into Sophos Central to do some reports and there's not data from my firewall since 27 Feb (it's now 02 Mar, so no logging from the firewall to SC in three days). I do have updates to the AP (also on SC) set to happen on Sunday, so it could be related or could be coincidental.
This is the second time it's happened, I think both with EAP's but I can't remember. Last time, rebooting the firewall fixed things. (Can't reboot right now.)