Hmm, I also play on Stormbluff Isle and I haven’t seen any problems with the Mudbay event chain yet… So there are a few reasons the Sheriff might not be there. If the Recapture event was succeeded, it doesn’t restart, instead it kicks off the Defend Mudbay Digs event, which does not involve the Lionguard. The Defend event will keep cycling if it is completed successfully and the Lionguard won’t show up again until the Defend event has been failed and the Recapture event kicks off. There are also cooldowns between each event where neither event will be active. And a final possibility, if you see her Lionguard Squad but not her, the Sheriff might have got pulled into combat. The Champion Event at Overlord’s Waypoint sometimes pulls the Lionguard – check your map for a Fallen Ally marker, she might be resurrectable nearby.
I’ll keep looking in to it, though. Please post any more specifics as you see them, thank you!