Yes, in one of my old posts I have listed in detail the reason for this sequence. In short, if your application in complete it will be rejected at R10, so no point in proceeding further. Then if your are inadmissible based on Criminality or Medicals, then there is no point in doing the eligibility.
Only when an application has passed R10, Criminality and Meds, will the eligibility start, which is very Time consuming and takes 2-3 months and all documents have to be reviewed. Only after eligibility is passed, the security is initiated which is the last stage and is done by agencies such as CBSA and RCMP.
To read on stages see
https://bit.ly/2MrOcIG
Security see
https://bit.ly/3nxK6M5