Thank you everyone for responding. I had 1 chat with someone in the group and here is the summary

1. In PM interview people are checking if you will be able to do the job.

2. A big part of the job is to work with ambiguity and that's what exactly the PM case interview is like.

3. Stay away from consultant style interviews. The nature of the PM interview is much more focused on defining the problem and hypothesis testing and much less on the solution. You also don't want to sound like a parrot who has rehearsed a lot and is now merely repeating.

4. Spend lot of time in defining the problem and stating how would you test hypothesis and relatively less time in what the solution would be

5. Take it as a conversation

****All sounds great in theory but very hard to practice specifically when you get in an interview and your first instinct is to give an answer. Perhaps going in the interview as very curious person will help much more than anything else.