A neighbor and were discussing that very thing during the last goal set. We had both had that happen.
I have five each Bakery and Restaurant and have ample opportunities to gift and request parts between myself. There have been many instances where requested parts don't arrive, aren't counted, amongst other irregularities. Disappointing that the system is so untrustworthy.
Edit: Since I posted, this happened...all of a sudden, my goal progress has the 3 required ovens with a chech mark, meaning I have minimally 3 peach ovens. But I have only two completed peach ovens period and the box was gone. Where is that third oven? Seems impossible. I also think this means I lost an appliance slot.