This is bilboohicks, the scoredoom dev. As you may know I based scoredoom off a now ancient build of gzdoom (1.0.29).
I have found a weird bug which happens in vanilla gzdoom 1.0.29, but not in vanilla gzdoom 1.1.00. I noticed it happens in Deus Vult 2 when certain sectors lower to the floor, and when my add-on pack is loaded.
What happens is that when the sector is lowered all the way, the resultant floor texture is missing. I'm not a mapper, so I'm kind of perplexed. I've found that when I take content out of the add-on pack wad gradually, that eventually fixes it. I've deduced (I think) that it is related to the total lump count being over 32786 that this starts happening. I know there is a limit with Boom and segcounts @ 32768, but I cant seem to see a connection.
I was hoping someone could at least point me in the general direction (in SVN maybe) of what this could be, and its fix, since gzdoom 1.1 has it working. I realize I'm talking about an older build of gzdoom, so I'm cool if you want to tell me to stuff it

I have an example: DVII, Map 21, Unholy Cathedral, right near where the chaingun over the pentagram trap is.
I activated a line special 200 via a switch and a bookcase drops, revealing the skybox (taken in scoredoom, but happens in vanilla 1.0.29 too)
This

goes to:

This causes crashes sometimes too, especially in scoredoom where actors/ custom player cross over the void.
Again, thanks for any pointers/help.