Sprites would randomly flicker with red (rarely blue) fullbright color. Barely happens on maps with low sprite count, but very noticable on bigger (1000+ enemies) maps. Even noticeable on the start of Doom 2, during the screenwipe two zombiemen and armor pickup would be lit up red, but rarely happens otherwise since sprite count is low.
To reproduce: * Fresh install GZDoom * Launch once to generate .ini * Set CVARs mentioned above to the said values. * Load map with big monstercound and have many monsters on screen. * Move mouse around and see the flicker.