> Verifiers SHOULD permit claimants to use “paste” functionality when entering a memorized secret. This facilitates the use of password managers, which are widely used and in many cases increase the likelihood that users will choose stronger memorized secrets.
https://pages.nist.gov/800-63-3/sp800-63b.html
I use the "Don't Fuck With Paste" add on for Chrome/Firefox, which mostly works well.