I had an in-depth, 45-minute HR screen where the recruiter couldn't provide any technical details, deferring them to the next stage. A few days later, they informed me they are 're-evaluating' the role and are unsure who they want to hire. When I pointed out the waste of time, they used the 'fast-paced startup' excuse to justify their lack of preparation. Interviews are a two-way street. If you don't know what you're looking for, don't interview. It felt like they were A/B testing the market at the candidate's expense.