The bug triggers by taken more damage than 1/2 of your final heart if you set it to peaceful than set it to easy or higher it will regenerate normally, if you take damage more than 1/2 on easy or higher it won't regenerate last 1/2 heart.
The bug triggers by taken more damage than 1/2 of your final heart if you set it to peaceful than set it to easy or higher it will regenerate normally, if you take damage more than 1/2 on easy or higher it won't regenerate last 1/2 heart.