Wrap some kitchen cellophane around it to hold it together until you find a proper size container to be able to slip pot. If it is not possible or you don't like the idea, in my opinion a little bit of rootwork to fit the pot will not cause any harm if the tree is healthy
i was thinking of trying to wrap it somehow just didn't know with what, but i think the cellophane might work.
if not, the tree is indeed healthy and both pots are 4 quart containers just slightly different geometry like mentioned before.