So for the past few days, I invaded Portugal and tried to take Kairwan, a tunisian province. At first, I hit it with about 15 hit point strong infantry. Weirdly enough, I can't see the strength of the unit defending and the fortress has been destroyed since the first attack, but I can never take out the unit. I asked an ally (Greece) to take it out, but they confirmed that they can't see the unit strength either and failed also. Also, this is in both Legacy Mode and the new Mode.