Given that I know for a fact I have had to decrypt this pool with the passphrase stored in the password manager in the past, my best guess is that I accidentally over wrote the passphrase stored in the password manager at some point. I have been making a lot of changes lately, and it’s possibly that I stored the password for something else over the passphrase for the drive encryption by mistake. I am not aware of anyway within in the password manager to see when it was last updated, so this is just a guess based on the available information.
Edit: This is for sure what happened. I found the modified date in the password manager that is after the creation date. Unfortunately when I went to look at the password history it did not show anything.