Pathfinder #1, Fast Healing and Regeneration are bugged, Fast Healing still healing monsters and players even after they have died and will not auto stabilized if there not dead as in the rules when healed; Regeneration is working ok until a monster takes damage to by pass Regeneration when its dead at -(hp + con), it stops it for 1 round, when it takes the specific damage like Regeneration cold at negative hit points, the Regeneration should stop for good not just for one round

Fast Healing (Ex)
A creature with the fast healing special quality regains hit points at an exceptional rate, usually 1 or more hit points per round, as given in the creature’s entry. Except where noted here, fast healing is just like natural healing. Fast healing does not restore hit points lost from starvation, thirst, or suffocation, nor does it allow a creature to regrow lost body parts. Unless otherwise stated, it does not allow lost body parts to be reattached. Fast healing continues to function (even at negative hit points) until a creature dies, at which point the effects of fast healing end immediately.
Format: fast healing 5; Location: hp.

Regeneration (Ex)
A creature with this ability is difficult to kill. Creatures with regeneration heal damage at a fixed rate, as with fast healing, but they cannot die as long as their regeneration is still functioning (although creatures with regeneration still fall unconscious when their hit points are below 0). Certain attack forms, typically fire and acid, cause a creature’s regeneration to stop functioning on the round following the attack. During this round, the creature does not heal any damage and can die normally. The creature’s descriptive text describes the types of damage that cause the regeneration to cease functioning.
Attack forms that don’t deal hit point damage are not healed by regeneration. Regeneration also does not restore hit points lost from starvation, thirst, or suffocation. Regenerating creatures can regrow lost portions of their bodies and can reattach severed limbs or body parts if they are brought together within 1 hour of severing. Severed parts that are not reattached wither and die normally.
A creature must have a Constitution score to have the regeneration ability.
Format: regeneration 5 (fire, acid); Location: hp.

Stable
A character who was dying but who has stopped losing hit points each round and still has negative hit points is stable. The character is no longer dying, but is still unconscious. If the character has become stable because of aid from another character (such as a Heal check or magical healing), then the character no longer loses hit points. The character can make a DC 10 Constitution check each hour to become conscious and disabled (even though his hit points are still negative). The character takes a penalty on this roll equal to his negative hit point total.
If a character has become stable on his own and hasn’t had help, he is still at risk of losing hit points. Each hour he can make a Constitution check to become stable (as a character that has received aid), but each failed check causes him to lose 1 hit point.