[hc gamer]

No, it was only on turn 6 or so that I noticed, no special events and no special attacks.

It was on Aran.
I must have started around province 9 (bottom right), and maybe had 2-3 provinces under my control. I had "information" (that you get thru dominion) on about 6 or so of the surrounding provinces (e.g. 22, 30, 18, 13, 4, 2), but no dominion anywhere else. Except over on the middle left, I had a dominion of 2 in 20, a dominion of 1 in 28, 36 and 34, and maybe 26 too). Where no prophet, pretender, or dominion-spreading device (juggernaut, ark etc.) ever was. Remember it was only turn 6.
Weird.