I use arena1-3 specific omnibars that are positioned next to the arena frames of each player. The bars don't update to the new enemy player classes between rounds of Solo Shuffle. This seems to be because Omnibar relies on either PLAYER_ENTERING_WORLD, ZONE_CHANGED_NEW_ARENA or UPDATE_BATTLEFIELD_STATUS events to call OmniBar_SetZone which effectively resets the class <=> bar association (which gets called in many scenarios but not between SS rounds).

A simple fix that works for me is adding:

        if self.settings.trackUnit:match("^arena") then
            OmniBar_OnEvent(self, "PLAYER_ENTERING_WORLD")
        end

to the GROUP_ROSTER_UPDATE handler within the OmniBar_OnEvent() function. There might be "better" fixes, but figured I'd offer this one for consideration.