Nope, that date means nothing unfortunately. My due date was 1 year from AoR ie 18th Feb 2021. Not even a byte of data moved on my file that day or even till today. My Security has not started. Info sharing in progress (Info sharing all data from all countries is ready, some officer needs to open, look at the data, approve and mark the security done). For fully completed COPR files, the Security field in GCMS shows empty i.e as if its not applicable. I think they just clear the Info sharing process to done and that triggers the DM. And someone else opens the file to take a final look and release the COPR.
Just call them to get an instant update if your Security started or not. Also, you seem to be my best friend

the first candidate (like me) to start outland and turn inland midway.
Please refer to this
completed GCMS (COPRed already) from one our kind friends from this group :