Hi Kijeta,
That is an odd case, yes. I don’t know for certain, but my best guess is that the hopper will win out first, but the high zone flag for capping will also be increased to 3. This means that if you make another chargeable journey (bus/tram or train) it will deduct a charge to take you up to the zone 1-3 cap.
Do let me know if you ever try it out!