The problem is that at Step 4, the downstream customer refuses because they feel they have been deceived by the wrong price listed on the unaffiliated website. In turn, the courier refuses to pay and the restaurant is stuck with the unsold meal they made.

I suspect that in some cases, it may be that the downstream user has might already have paid with their credit cared before step 1 has even happened. The delivery-related operations staff are trusting their site's own prices, which are wrong due to some other employees not updating them.

Then they realize at step 4 that if they buy the meal at the correct price, they won't make a profit any more.