I have the same problem. I use Requiem + lots of patches for mods and always reorder my loadorder because LOOT makes the worst loadorder for Requiem. Weirdly, my game only crashes when i load the newest save. When i load one i made before it works fine. And my game isnt even starting when i install a new mod, even when it is something simple like the "Equipping Overhaul". Really wierd stuff