I think that glitch (stuttering and missing enviromental texture) happenes only with some Miha's mods, never had problem with vanilla cars or other mods, only Miha's. No all of them, but most of his bigbnk's mods have that problem (for example his corvette pack works for me except 2014 Stingray and 2014 Hennesy Stingray). I can't also alt-tab to system and back, game just freezes when alt-tab back, that's another sign that something is wrong. It never happenes (at least to me) with vanilla cars or other mods, only with some of Miha's bigbnk's mods.
Don't know if it's related to some hardware configurations, all I know is that glitch appeares after 15-45 minutes of driving. That time differes from car to car. CPU and GPU temperature was perfectly fine, also RAM and VRAM wasn't filled up, there was plenty of room.