Regen beacon doesn't work

My health doesn't regenerate, even though I have the regen effect from a beacon.
natural regeneration is on

Steps to Reproduce:
1. take damage
2. make sure hunger is low enough to not regenerate that way
3. be in range of regen beacon
Observed Results:
My health doesn't regenerate, even though I do get the regen effect from the beacon.
Expected Results:
My health regenerates

(note: a relog fixes it, temporarily)