I also got BPLUS/APLUS notification yesterday for $10 off but like others it didn’t work for me either.
However, today I just checked eBay plus items again in the evening and got customised code starting with BPLUSXXXXXXX under eBayPlus items and was able to apply it at the checkout.
May be its targeted too but not sure.
The screen is now showing “Check my eBay for code”
Please check your my eBay page.