Hi everyone,
My MIL also didn't get a "valid until-date" stamp on her passport. I phoned CIC and the agent emailed me the ff. The link doesn't work here, so you can just search IMM 1436E for the application form stated below...
Thank you for contacting Citizenship and Immigration Canada. I am pleased to follow up on your request:
Super Visa - Length of Stay - Less than 2 Years
Please note that with the Parents and Grandparents Extended Stay Temporary Resident Visa (Super Visa), eligible parents and grandparents are able to remain in Canada for an authorized period of up to two years.
If the length of authorized period of stay indicated in your passport is less than two years (and your passport is valid for at least two years), or if no stamp was placed in your passport by the officer at the Port of Entry, please follow the instructions below:
Complete the application, Request to Amend the Record of Landing, Confirmation of Permanent Residence or Valid Temporary Resident Documents; and
Mail the application to the Query Response Centre in Ottawa, Ontario.