In dev mode, there is something to view the object count or load, which amongst other things, also shows how many AI aircraft are loaded in. Once you turn traffic off, is anything still listed in object count?
There was/is a bug, where traffic wasn’t/isn’t getting cleared properly on a return flight or after turning it off. It also seemed to affect 3rd party traffic like AIG and FSLTL. Here’s the link to that bug - "Fixed live traffic planes getting stuck at the center of the airports" Not Fixed - #128 by BuckledImp22303
I’m not at my computer to check where this is in dev mode, sorry, and I’m avoiding loading FS anyway until the bug at the top of the forum is fixed.