Cleon
Legend
There are two reasons I don't like rapid healing. One, the original gives no hint of anything like that. Two, constructs can't heal on their own unless they explicitly get fast healing, etc, so I think you need extra justification to add it to a construct.
I've long preferred that golems that seem to basically be artificial lifeforms (such as Flesh Golems) to be able to heal their wounds. Besides, I don't recall any clear statement in official AD&D sources that Flesh Golems don't heal like living flesh and blood.
The Nyraala Golem appears to be made of living fungus rather than flesh-and-blood, so I would live it to have some autohealing ability.
What about the notion that it heals at the same rate as a living creature (1 hit per HD per day) when in Fungus Form?