That's odd, was the delay in collecting on your side?
The expiry date is typically one year after the medical evaluation, so not unusual on that part, just wondering why it was there for eight months.
At any rate, I think you have two options:
1) Do not attempt to get it 'fixed' but apply for authorisation to travel as per this page on expired visa/coprs (this is covid-related):
https://www.canada.ca/en/immigration-refugees-citizenship/services/coronavirus-covid19/immigration-applicants.html#approved
Under the instructions you should do this when you are ready to _permanently_ resettle in Canada. And provide additional documentation, etc.
2) Go back to embassy and attempt to get one issued with a different expiry date. I've no idea whether they will even do this.
But: in both cases they MAY request a medical evaluation again (hopefully not).
My suggestion would be to determine when you wish to go to Canada and if you can and you wish to go relatively soon, go for the first option above. (That may be in fact be the only option and you may have trouble even getting anyone to respond about whether the second approach is possible).