Same problem on my end.

I have encountered the same problem - when can this be fixed? Thanks

Same...

Same problem, please fix the bug

I just spent close to an hour over the phone with turbotax and their conclusion is the problem is with Revenu Quebec requiring the TP 64.3 for Netfiling

This makes no sense. If an employer provides a TP64.3 to you it would mean that you would surely NOT file the simplified claim; you would obviously choose the detailed method which is substantially more beneficial.

https://www.revenuquebec.ca/en/online-services/forms-and-publications/current-details/tp-59-s/

The above link CLEARLY states that if you complete part 1 and 2 of TP-59-S-V you do NOT need a TP64.3.

TurboTax: stop feeding users incorrect information AND FIX YOUR SOFTWARE!!

Just spent some time over the phone with Revenu Quebec /IT support. In years past, form TP -59 required you to have a TP-64-3, but for tax year 2020, form TP-59.S clearly states it (TP64.3) is NOT required for the fixed rate method (section 2).
They realize there is a problem maybe and will have to get back to me within 3-4 business days. 

I will follow up here after RQ gets back to me.

experiencing the same issue. Any updates Turbotax? 

Same here, just purchased turbotax and wanted to do it early... just to run into problems. CRA went fine.  Revenu Quebec is a no go.