So after continuing playing and keeping an eye on this here are a few thoughts :
Maybe the disappearing parts are part of the refunding process. The slot decides a bit too soon that as it is producing a featureless car it doesn’t need the more expensive parts and frees up the stockpile. The issue is that as soon as that car leaves the slot, it orders these parts again because there are other cars needing those upstream.
If these parts are indeed refunded, it’s not made clear as we have no hint of that process happening. There’s nothing that says anywhere : “You’ve been refunded that certain amount”. As such we don’t even know for sure if a refund has taken place unless you’re on a very slow line with not much happening and you can see your cash balance going up at that very moment. I know refunding is supposed to be part of the game because I watch the devblog, but I’ve never witnessed it for sure.
From where I sit the only thing I can see is that my imports and consumption of these very expensive parts is skyrocketing. It also puts additional stress on the supply lines, and I suspect it burns cash as well.
In the game that I’ve shared, I worked around the issue by building a dedicated line for budget cars, only upgrading the few slots that needed it and kept my fully upgraded line for luxury cars, which I would run only for short periods of time and let it sit idle most of the time (the new pause slot button helps a lot for that). Before that I was just keeping afloat but with the new line I immediately started making profit again despite having almost twice the workforce for the same job.
This leads me to believe that if this is part of the refunding process, then maybe it is broken in a way that it doesn’t refund anything. If not then the slots are just behaving wrong, burning parts on the wrong cars.
This also makes me wish we could keep track of the refunding process because right now we don’t know if it’s happening and when.
Thanks for reading this, I hope I’m not making it longer than it should.