Concourse Labs interview questions

The interview process was straight forward - no full day panel interviews. The conversations were mostly informal, back and forth exchange. I was offered a letter of employment. There were a few red flags during the interview process - mentions of churn, negative reviews of past employees, etc. I enthusiastically replied but said that I would take a few days before giving a decision. In the morning, the offer letter was rescinded. Thank God I didn't accept and give notice to my current company!