Try to disable the unofficial patch, I can't say that's the problem, but after disable mods one by one, the result is that the patch is the cause of these legendary picking up crash, which is sadly since it did kill some annoying bugs in the original game. Or, download the "No Feature Items" to skip the inspection menu when picking up legendary items, and never inspect any synth/combat legendary armor in the rest of your game play, hopefully the unofficial patch team will find out the reason soon enough.