Mine is the same, PR AOR was also May 16 with no medical updates etc. The status just says 'It has been received...'.
I actually called this morning about the BOWP and at first they said I didn't have a PR application! (EEP!!!)... but once I gave them the number, they confirmed that it does indeed exist but that it's not yet linked to my BOWP application... which is why my BOWP application is now on hold.
She said this can sometimes take some time and couldn't give me any indication as to how long that could be (only that is has to be within 6 months as that's the PR processing time). Basically it looks like your PR application needs to get to a certain stage before they can approve the BOWP.
I've actually been on implied status for 6 weeks already and have a trip out of the country booked for this Wednesday.... it's looking like that will need to be cancelled now