Thanks for your responseYEs, they can. If your COPR has not been issued, then before one can be issued it is made sure that your medicals on file are not expired or expiring before you land as medicals have to be valid both when your application is being processed and when you land.
If your meds are expired or have expired, they will be sent for reassessment and can be either extended, or you may be asked for remed, will depend on the assessment by the Regional Medical officer.