I generated a password using words mode and I edited to add a number to the end, but when I clicked save and it auto copied that passcode, the number was not included which caused me to set the wrong password unknowingly.
What version of the 1Password app are you currently using?
Thank you for the confirmation @kennedy513. I have just tested this and I could not reproduce the issue (after adding a number at the end of the word-based password and saving it, the correct password was copied to the clipboard).
Are you able to reproduce this consistently?