So just found something new today from March AOR thread.
All these days I was under the assumption that 6 month timeline basically starts from the date of AOR but that is not the case. As per IRPA regulations, the 6 month timeline actually starts from the date R10 checks were completed.
So my R10 check was done on December 17, 2018 and now that makes sense why my application completion date is pushed to June 11, 2019