Error on client close
 

I seem to get this error after /camping.
The error happens ~80% of the time, which is odd. Not sure how to reproduce it.

I am running Win10 fully patched, with a fresh install of P1999, and a fresh install of WinEQ2.

It's not a big deal at all since it only happens when my client is closing; I'm just curious as to what's causing it - and if there's a simple fix or not.