Platform, device and operation system
Samsung Galaxy s20
What were you expecting to happen, and what actually happened
The description for th regeneration effect from the serpentine ouroboros ring says that it heals 2% of max health per turn. It actually heals 2% of current health per turn. So if you are nearly dead you will end up healing zero hp per turn.
How often does this happen? When did it begin happening?
Always
Steps to make it happen again
Equip the serpentine ouroboros ring
Match gems to activate the regeneration effect
Observe that at full health, 2% of max health are healed per turn
Take damage
Observe that the healing amount is reduced proportional to the damage taken