Which board minions first moves ... We decide by rolling the rune die.
And than we start from that board /according to the colour compass/ clockwise. The conflict is mostly connected with the oil slick spots, which can throw a minion to the other end of the map /over the opposite board/. So if this happen we move that minion and if the present board colour is after the board colour from which the minion come .. we move this minion again /if able/.
Minions should never be 'thrown' to the end of the map via oil slicks. Once an oil slick is exited, sliding stops.