Tell me about your hiring process — how many rounds, how many interviewers? Is there anything special about your interview process I should know? Are coding interviews on a whiteboard or laptop? What resources do candidates have access to while coding? Assuming the process goes well, how long does your hiring process typically take? How long do candidates who are given offers have to decide on an offer?
are perfectly fine, because they're simple and objective, and can be immediately answered by the company (if they have their shit together on any meaningful level). But questions like:
What are you trying to figure out about a candidate in an interview? Why do you think your current process does that effectively? What biases have you decided to accept in your hiring process? Which are you trying to change?
would be a red flag, because really now, it's not like employers have huge swaths of time available to holistically explain the raison d'être of their hiring process and how it got that way. If anything it's the exact opposite -- if they company is successful, then their people have almost no time at all to wax philosophic which each and every candidate about such topics.
So to ask questions of the latter sort strikes me as a bit obtuse.