It is my understanding that rooms that connect through a door in the wall don't connect through the balcony due to where the doors to the balcony need to be. Their balconies connect to the balcony on the other side. So rooms can connect through EITHER a door in the wall or the balconies, but not both.

Most, if not all, cove balconies on the Vista do connect if they are not connecting rooms by door. (That may not be true for all ships.) We are in connecting rooms (by door,) on the Vista. Our balconies would open to the cabins on the other side of us.

I hope that all makes sense!☺️

This page has all connecting balconies listed:

Edited to add that some ships have balcony cabins that connect to inside cabins. I'm not sure which ships have this, and there are very few of them.
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01-20-2013 Carnival Conquest
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