Hi Nicole...
No, I am not saying that is the precise factor that would delay your application. Logically speaking, if CIC needs any police certificate, they will ask you to provide them and they will give you some time.
Regarding Canadian police check - I could be wrong but as far as i recall it was written in the guide that if a Canadian police certificate is required - it will be asked. you don't have to provide it along with the application.
If you have already requested for GCMS - that might help you in telling why your application is delayed. At the same time, if you are an August applicant, you may be aware that there are still some May, and many of June and July applicants waiting for their MRs. So I'm sure yours will come soon too. Don't worry.