Vindman was relocated for being a gossipy little brat while thinking he ran Ukraine foreign policy, as well as being a security risk because Ukraine thought it was okay to ask him to be their defense minister. Sondland was relocated to private life because he acted like a buffoon and ran his mouth too much without getting instructions from the President. No one was relocated for only testifying about their own incompetence.
If nothing else, ambassadors should know not to speculate...and when to keep their mouth shut.