And as someone else also pointed out, NIST (US Gov National Institute of Standards and Time) explicitly allows this behavior.
Furthermore, another workaround is using the Mac version of the software, which doesn't have this inane restriction. I'm glad Credit Karma is improving its tax product so I and others, who are disappointed with inaccuracies and sub-standard support, will have other options.
Ref:
https://pages.nist.gov/800-63-FAQ/
https://www.thesslstore.com/blog/nist-password-pasting/
