Frustrating hiring process.
The HR screening was easy enough.
The other people are right, they are very vague about what they're expecting for the technical portion. The HR person made it seem easy enough, and that it was an open ended discussion about a technical problem they're having. I read the case and prepared a lot for it.
I was ready to discuss the problem but their interviewer seemed confused about my answer and kept asking me further questions expecting a specific answer. When I asked clarifying questions, the interviewer seemed frustrated I was asking them and spoke condescendingly to me instead of telling me what his expectations were in my answer.
Seems more to me like they're looking for free solutions rather than just tell you what their expectations are.