I'm trying to add a pet to my party, I have the space.

But I keep getting 'There was an Error: This pet is too high of a level for you to command.'

I wasn't aware that was a thing. Why is it a thing?

It probably isn't a bug.

To counteract newer players from just buying themselves to higher levels, Krin made the party system work so you can only equip pets that are leveled up to the highest pet you own. If the highest level of the pets you own is like 35, but another pet that once belonged to someone else is 36, you can't put it in your party.

Even if you're the one that leveled it to the level higher than your own pet's, it won't let you add it to party. o: You'll just have to level up your highest level pet so you can equip the other pet again.

This cap system will be improved - maybe this week. But if not, relatively soon.