I might be misunderstanding how this is supposed to work, but if I use "Generate Password" from 1Password Mini on the Mac, attempt to copy and paste the password, the one that is generated on screen is different from the one that is pasted.
I have tried:
See Video for Walkthrough Details:
1Password 7.8.7 App Store Version
1Password Version: 7.8.7
Extension Version: Not Provided
OS Version: 11.5.2