This has been my experience as well, and I have been living in central Bangkok, so I suspect this is not just a Doi Saket/Chiang Mai thing! The problem seems to be that there are very few people who bother to update the inventory on the Grab terminal, so they find out only too late when the delivery rider arrives and they can't finish the order.

Every time this happens, I feel awful for the delivery rider who had to go all the way there, only to not get paid because the order wasn't completed.