Buffer underflow

My client crashes with this message EVERYTIME in a pen map (not only there, but here it seems to be repeatable)

same problem, pen and graveyard maps

I get this in maps that I've had no issues in previously...

So far can confirm:

Pen
Factory
Haunted Mansion
Museum

I have the same issue in Graveyard map, client crashed 3 times cause this "buffer underflow"

Getting this often in Seige map

Getting this crash after about 1 minute of entering a map. After the first crash I figured it was a rare one off thing, I have not had a crash in maybe a year so i continued playing. I was able to run an entire temple of atzuatl without a crash but after exiting back into the map i crashed 15 sec later. The crash is now consistently every 10-30 sec after entering a map.

The Dxdiag exceedes the 50000 character limit, how to proceed?

Have crashed about 10 times so far to Buffer Underflow. Twice in Pen in 1 minute before writing this message. I think previously in Graveyard also, not 100% sure if it's repeatable in certain maps or not.

i'm getting the "buff underflow" and "Activation failed, unable to open portals to area." a lot since yesterday..
pls halp

Can confirm, Pen map.

7700HQ
GTX1060

Maze Map for me.