Eppo interview questions

The first few interviews were simple enough and I guess I had misconstrued the presentation so there was no offer (my bad). The part where I rate the interview poorly is both in the unofficial background check and the final feedback. The Eppo hiring manager happened to know someone from the company I was working at, and basically contacted my then-boss who didn't know I was applying to Eppo. So imagine my surprise when my then-boss confronted me with that. Eppo hiring manager did apologize, saying he didn't mean to get me in trouble, and that his contact automatically connected them together. So hopefully that's a one-off. After my presentation, I was told by Eppo HR that they'd get back to me latest, by the end of the following week. I waited that week with no word, so I followed up with them and it was only afterwards I got an official response from the hiring manager that they decided to go with someone else. They are totally fair in whatever candidate they chose, but I thought it either unprofessional or just plain cowardly to not say anything until pressed.