Not related to this specific promotion just to ebay promotions in general...
I spend $2-3K on used hardware every month and I noticed a few things. I usually get some ebay bucks bonus (i.e. 5-10% vs regular 1%) every few days. But I never get any promotion offers when I have any pending offers. Also if I submit an offer while I have an active promotion - often the offer gets accepted within an hour after the promo expired. It feels really fishy to submit an offer during business hours to a clearly business account and see it getting accepted shortly after midnight. Feel free to call me crazy.
There may be some truth to some of that for sure. Wouldn't be surprised in the least if there are some basic algorithms surrounding offers going to members based on their activity.
I did get the 10% in-app bucks offer today. Mine was set to expire on 09/18 though (tomorrow...), not 09/30
Maybe it's a Canadian thing, or maybe it's a personalised expiry date
EDIT: nvm, this is a promo code, not in-app thing. Derpy derp nothing to see here