Hi Minusham,
I'm June 2nd applicant and haven't had a MR yet! Little bit worried but all we can do is wait a few days and maybe order GCMS notes.
I'm no longer with my employer and have since left Canada due to Work Permit issue so have no idea if they called my previous employer.
They are most likely just checking up and doing a thorough check on your application. Hopefully we both get some good news in the next few days!
I'm trying not to get too stressed! If I hear anything from CIC I will post in forum.
Good luck to you and all June applicants.