Josephf-
I posted some a while back. I don’t have time to go into details now but here are two.
1. (In Eretz Yisroel) Same shadchan tells two friends, both named Dovid, to meet their dates at the same time at the same hotel. First guy walks in and a girl says to him “are you Dovid?” he smiles politely and says “Yes”. He later suspects something is off but didn’t figure it out until he met his friend Dovid also on a date. They both realized they were dating the wrong girl so they switched dates. I don’t know if any of the four possible matches worked.
2. A shadchan wannabee thought of a great shidduch but needed approval from her mentor, a “professional” shadchan. The “professional” thought it was such a good idea and decided to suggest it herself so she could get the shadchanos. To make a long story short she told the guy about the wrong girl, they went out got engaged and got married.