Not sure if this is intended, but I do not think so.

With the new bubble columbs you get sinked onto the magma block, and you won't be able to "recharge" your breath within that time, if the new mechanics gets implemented that is if you go to the surface / into an air block you will slowly get back your oxygen. I heard that that is going to be implemented soon.

Also with this change, it would be kind of obvious that this is not intended behavior, but I might be wrong.