ToME: the Tales of Maj'Eyal

This is something that has happened to me a few times in both 1.2.3 and now in 1.2.4 with Ash DLC. It has happened with multiple classes and characters.
When using a melee character, at some point suddenly the accuracy just gets set to 0 permanently. I tend to find out after the fact when I suddenly can't hit anything which means I'm not necessarily able to exactly pinpoint when it happens or whats occurred to trigger this. It tends to happen in the mid-teens or early 20s.

Has this happened to anyone else? If so does anyone know what the trigger is and how to avoid it.

I have included the character dump of the latest character with this problem.

This just happened to me as well, shortly after being hit with an ability I had never seen before. I didn't inspect the monster before killing it; my HP then went to 0 (without killing me) and remained there for several turns despite my attempt to heal myself. Then suddenly I was back at full HP. I noticed that my accuracy was completely gone while fighting a boss on the following floor. Adding or removing accuracy-changing gear and skills does not appear to affect the issue.

Character is a Shalore Doombringer, level 15.

This happened to me again. I looked at my gamelog and also included it here. The accuracy seemed to have become zero after I killed Xanyrada the water imp.
Possible triggers (events which occured in game) include
Curse of death - but shrugged off
Acid splash
Blood lock
Hit with water siphon

I've included the relevant parts of the te4log file to see if it may help in finding this bug.

I am using several addons including nullpack, weapons pack, everything is unique, ashes of urhrok, slightly more adventurous and tomes of knowledge.

I can also confirm this: happened to me with a Crystal Transcendent Fist (nullgems + nullpack addons).
It may have been after a strange occurrence where a (unique version of a huge acidic devourer)'s acid area attack hit me for minus 9007199254740992 health (rather than the typical positive 5 - 20 per turn).

That character also acquired NaN armor (that is, the armor value was NaN -- Not A Number, which confusingly enough is a 'numeric' value) and NaN defense; a while later, it glitched irretrievably. The dump on te4.org also became .. wrong (the character description shows up, but nothing else shows at all)

For me, the problem occurred as I was beginning in the East (so, later than you -- level 32?). I had just completed Vor Armory IIRC and was going through the sand cave.

There must be a screwy value on acid somewhere.