Read this part:
What does s.15 / s 16 information withheld and blank pages in GCMS notes means?
When you see a blank page or pages in your GCMS notes with s15 or s16 at the right top corner, this is what it means:
These sections correspond to the s 16 and s15 of the Access to Information Act, same act under which your request fro GCMS notes.
Section 15 pertains to "International affairs and defence;" and
Section 16 pertains to "Law enforcement and investigations"
IRCC can refuse to disclose specific information under any of these two sections.
What does refusal to disclose information under these sections mean and how it impacts the application?
1. Section 15 -
Information under this section is hidden when IRCC or a Canadian agency has requested information from a foreign government or agency. It could be anything from checking your record in a foreign country to verifying the information you have supplied in your application. CSIS also requests information on your criminality or association with terrorism if they suspect any. However, most people who would see this would be those who have worked for foreign governments, especially military. Most of the applicants who see this on the GCMS notes, need not worry, as this is a routine check and does not impact the application. It may delay the application, but will not be harmful, unless IRCC finds something seriously wrong.
Also go to this link lots of really good stuff from the GCMS people!
https://www.canadavisa.com/canada-immigration-discussion-board/threads/all-about-gcms-how-to-order-read-general-questions-answered.482200/