Slack Frontend Engineer interview questions

Had a contact there who got me a phone screen scheduled with a recruiter on a Friday morning. The recruiter emailed me 3 minutes before we were supposed to speak saying he wasn't going to make it, but to email him any times I'm available for the next week and he'd be sure to make time. I sent him two times, one Monday morning and one Tuesday morning. Monday rolled past with no response, so Monday evening I emailed my contact there who nagged the recruiter and got them to confirm me for Tuesday (the email confirmation came in at around 9:30pm on Monday). On our call he was clearly reading from a list of questions, and not really willing to engage conversationally - seeming rather checked out from the conversation. In addition, it sounded like he was eating his lunch while we spoke, with what sounded like chewing noises throughout. I felt like most of the questions should have been for more of a Product Manager role as opposed to an Engineering role, as they were more about features they could add to Slack or new apps I liked and why. The entire experience with the recruiter, from initial contact until the end was very rude and unprofessional. I felt like I'd been written off as a candidate prior to even talking with him, which made me wonder why he was wasting both of our time.

A recruiter contacted me via Linkedin. Had a 30 minute conversation with her, where she explained the interview process. Then, I got an email with the link to an exercise to be completed within a week. I worked on the exercise for a few hours. The exercise itself is straightforward and it does demonstrates front end abilities. I didn't get passed the exercise step, but what I dislike is that they give zero feedback about why the exercise wasn't accepted.