I am doing a whole base with the new copper mesh walls and exploded 2 copper nodes this week with no problem. I mine a circle around the node, then below it. Once I am comfortable that it is complete I hit it from the bottom and whole thing explodes. The side walls have to be a little farther than you just seeing empty space. In my experience about 4 meters on all sides works. Do not go too deep though or you will be back to trying to get on top and falling when the node explodes. Definitely still a thing though as I can still do it with no problems.

I do not even start one near shore as the water level can ruin a whole node.