additional document.. not applicable?

[neonlin]

My AOR is 27 Dec 2017.

After 2 weeks later, status showed me "my medical exam is passed."
and additional document was "we do not need anymore document."

and month later,
BGC was changed. "We are processing your background check."
and they asked me to pay RPRF.

Suddenly,
One week ago,
medical showed me "You do not need medical exam."
additional document "not applicable"

I am super confused.
Is there anyone have same situation with me?

 

[Rayan12]

https://www.canadavisa.com/canada-immigration-discussion-board/threads/additional-document-status-from-not-applicable-to-we-dont-need-additional-docs.483817/