I have the same problem using TurboTax self employed on line, and there are two issues with form 4684.
1) TurboTax is using the 2020 version of the form, the 2021 version is available on the IRS web site
2) One of the first entries on the form is "... and enter the DR-_________". The form is expecting the 4 digit FEMA assigned disaster number (4609 in our case). What TurboTax is putting in this space is DR-4609, so the end result reads "and enter the DR- DR-4609". When California receives this form, their screening S/W is expecting 4 digits in this field, instead it finds "DR-4609" and rejects the return due to an invalid FEMA disaster number.
