Again, we are aware of the issue. But, you can override line 20 and still NETFILE. If you go through EasyStep Mode, it will do the override for you.
If you are getting the Error "You reported First Home Savings Account (FHSA) contributions but haven’t indicated if you opened an FHSA in the year.", that's because you've removed the check mark on Line 68930 (Did you Open an FSHA), but have FHSA contributions entered.
