I recently noticed there was a patch released for the PS4 (back in July patch 1.06). It fixed my persistent trade crashing issue and generally the whole game crashed less as well. However, I just encountered it again after probably 30-40 more hours into the game. Now, in this time I have actually been consolidating all of my junk and crafted items by selling them to Thelyron so that when he leaves the game he will take the items out of the game with him (hopefully?).
One other factor that I did was I amassed a huge amount of crafted items on Anna and then just recently killed her for them all back. I picked up a fair amount of the items and loaded my inventory while still leaving probably 10x the amount in my inventory still on the floor. The game gets extremely laggy when I am on top of the pile or very close to it but it has not crashed. The crash I got was actually down at the skeleton trader by the Harbour so very far away from the pile. How many items would you actually have to craft to reach the maximum items in game? Could this just be more of an inventory issue on my character holding so many items?