Q. Today I got my employment authorization extended for 1 year, but states: “not valid for re-entry.” The visa I originally got 2 years ago was “multiple entry.” Is this accurate?
Answer: When you extend your employment authorization, your visitor record is extended as well. This means that you are allowed to remain in Canada for the duration of the employment authorization. A new visitor visa, which permits entry into Canada, is not issued, however.
It is not necessarily the case that if you leave Canada, you would not be re-admitted. Such admission, however, is highly subject to the discretion of an immigration official, which makes it difficult to predict in advance. On the basis of the information provided, however, I would expect that you would be re-admitted.
If you feel that you may have to leave Canada, then it may be worthwhile to seek a visitor visa in advance.