So you claimed experience from your previous employer, which you have the employment certificate from.
And you claimed 50points for valid job offer.
If this is valid than it is really problem with the employment certificate as you said.
The think is that you cannot connect current canadian employer and the documents, which you have provided with the documents from your foreign employer. Those are separate thinks and that's why CIC have problem with the employment certificate. They accepted the documents for canadian employer, because duties are, as you said, exactly the same as in NOC number, so you are safe with 50 points for valid job offer.
But documents from foreign work experience needs to proove that you really worked under the specific NOC code as well. So if you are missing job duties (or they are not sufficient) in employment certificate than this is a valid reason for rejection unfortunately :|
I would suggest to ask your previous employer to rewrite or provide written confirmation that indeed you had more duties than stated in the employement certificate (he probably will need to add that this was made by a mistake otherwise CIC still might not trust). Or maybe you have some letters/e-mails/documents that have those other duties listed for this previous job (example your depute asked you to do some duties, which fall under the NOC number). Everything like that might help to support your application.
And you claimed 50points for valid job offer.
If this is valid than it is really problem with the employment certificate as you said.
The think is that you cannot connect current canadian employer and the documents, which you have provided with the documents from your foreign employer. Those are separate thinks and that's why CIC have problem with the employment certificate. They accepted the documents for canadian employer, because duties are, as you said, exactly the same as in NOC number, so you are safe with 50 points for valid job offer.
But documents from foreign work experience needs to proove that you really worked under the specific NOC code as well. So if you are missing job duties (or they are not sufficient) in employment certificate than this is a valid reason for rejection unfortunately :|
I would suggest to ask your previous employer to rewrite or provide written confirmation that indeed you had more duties than stated in the employement certificate (he probably will need to add that this was made by a mistake otherwise CIC still might not trust). Or maybe you have some letters/e-mails/documents that have those other duties listed for this previous job (example your depute asked you to do some duties, which fall under the NOC number). Everything like that might help to support your application.