>I just need to travel to Canada 1 more time.
>In any case, if the TN is cancelled, can that jeopardize the GC process?
Each application, your TN and your EB Green Card, are supposed to be decided separately based on the merits of the application. Each application has separate criteria for approval.
If the CBP no longer considers your CSA duties meets the criteria of TN status, then your TN status will be revoked and you will be denied entry to US.
This is the main weakness of TN versus H1B. When entering on TN, each entry to the US, CPB can in theory "re-adjudicate" your TN status and potentially deny it. (I understand this is very rare, but your posts above show it is possible in your situation). When entering on H1B, the CPB cannot "re-adjudicate" your H1B status.
Your employer and employer's lawfirm obviously believe your education, experience and duties meet the criteria for EB Green Card (not sure if you filed EB2 or EB3, should not matter). I assume the I-140 has been approved and you are waiting for I-485 interview and approval.
During your I-485 interview you will be asked all the questions on the I-485 form, one of them being, "have you ever been denied a visa", to which you will have to answer "yes, I was denied TN status by CBP". It should not matter as the criteria for EB Green Card is different than TN status. Your I-140 was approved so you met the criteria for EB GC. But I am sure you will be nervous answering that question.
If you read my previous posts, I started on TN in 2015, tried to move to H1B in 2016 but was not picked in lottery, tried again to move to H1B in 2017 and was picked in lottery, but then issued RFE, then issued denial (specialty occupation). My company filed MTR and was ultimately approved H1B. Then the I-140 was filed and approved.
I had a similar question to my lawyer, "since my H1B was denied, will that jeopardize my GC application?"
He said, each application is decided separately, and since my I-140 was approved I should be fine.
But when it came to the actual Green Card interview and I was asked the question, "have you ever been denied a visa?", I was super nervous when I said, "yes, I was denied H1B, but it was ultimately approved", the interview did not even blink an eye, he just moved on to the next question. At the end of the interview he handed me a printout saying my GC was approved, wait for the card to be delivered in the mail.
The facts on my situation are different that your situation, so your choice.
If it were me, and I was so close to the finish line (GC interview), I would question if I really need to leave the US and re-enter one more time.
Good luck. Let us know how it goes.