Game Deleting My Item After a Rook Run

I just finished a rook run and came out with a huge backpack, but the game deleted some items when I came out. I'll explain the scenario.

I had just wiped the run before, so I went for a rook run on outpost to get a few weapons to then go back into a trios run. My vault was full, but I assumed that's fine as I had nothing on loadout since it was a rook run. Well turns out this was my best rook run ever on outpost where I got a purple backpack and tons of purple loot and purple salvage. My backpack was completely full on exfil and I was the last player on the map taking the final exfil. When I came out of the run to then clear out my vault overflow I noticed the purple salvage I got in the run wasn't there. I thought it had already gotten sent to my vault. Well it was a purple salvage I hadn't acquired yet and I didn't see it in my vault. So what happened was that I came out of the run with so much in my new purple backpack that my vault overflow was overflowed and the game decided that it shoud just delete my purple salvage to mediate that. I understand that I should probably clear out my vault a bit, but with the vault overflow system I didn't know that was a thing that would ever happen. 

Here's two ways I see how to fix this issue. The first way is to just increase vault overflow. I can't go back into a run with my vault overflowed anyways so just increase vault overflow to a point where nothing could be deleted even with a completely maxed out bag that would go into the vault. The second would be to set up a priority system on what items to delete first in a scenario like this. The game somehow decided to delete my purple salvage instead of the 2-3 rows of ammo I had at the end of the match. Why wouldn't it just delete the ammo first instead? In a scenario like this the game should just try to delete ammo and grey items, then greens, then blues, then purples.