Posting this here to keep track better.

Regeneration is bugged.

My friend and I have just tested it thoroughly.

Steps to reproduce;
1. Set health sharing mode to 2 or 3
2. Take damage.
3. Teleport to a town pylon. (of note, my friend and I are using a mod that allows teleporting to a pylon from anywhere. Still worth testing without that.)
4. Regeneration will stop completely for the host, and sort of flicker for clients, but will not increase the health of the party.

This bug occurs regardless of the buff sharing, deathlink, or team dependent options.

Will post again with more findings.