I would guess wind against tide (current).
For my boat - The wind always pushed the blow away. In very light conditions this is not so much of an issue. But in strong winds, the boat will continually ride the anchor seeming to tack from one side to the other. Now if you have a small amount of current from the stern it will actually provide the same turning motion that the wind is also providing and turn the boat stern to the wind. I refer to this as "wind against tide" and when I know it will be an issue, I always attach the long snubber so I don't get chain marks on the hull.
I suspect (guess) that the direction of the tidal flow in Eggs & Bacon is creating a circulating current in the bay which is acting with the wind to get the end result of boat riding up on their rode.
Well my thoughts anyway, and as usual I could be wrong again.
Pretty cold here this morning Don, what's it like in Tassy.