Database Encryption scan for database  was aborted. Reissue ALTER DB to resume the scan
Changing the account you use to run SQL Server means SQL Server is unable to unlock the service master key. 

The service master key is protected (encrypted) using the Windows Data Protection API, which includes using the machine key and the account key for the GMSA. 

When you change the service account, you prevent SQL Server from accessing the correct account key, and thereby prevent SQL Server from being able to decrypt the service master key, and in turn the TDE encryption key.

Changing the service back to the original account allows SQL Server to access the correct keys that allow it to decrypt the service master key, and thereby correctly decrypt all the other keys used in TDE.

I have a couple of related posts at SQLServerScience.com:


Filesystem Security and TDE keys
Cannot use Certificate, Private Key not Present