I’ve just started playing quick play weaves and natural bond does not work on bots - they don’t regenerate health, and drink healing potions like bots that don’t have natural bond equipped in the standard game modes.
I have not tested NB on a player character.
When I noticed this I was playing Waystalker and had the Amaranthe talent selected that gives health regen up to 50% of max to the entire party, and this works correctly.