Even if the warn was valid. The staff handbook says
4). Get statements from all sides before rendering a decision.
Chad issued a warning without Andre side.
Chad should informed the player to take the video and report to the forums as Andre was afk.
Or just jailed Andre till he came back and continued the sit.
EDIT: Also Staff Handbook says in issuing formal warnings
When you decide to issue an individual a formal warning, you must inform the person that they are receiving a warning, as well as why a warning is being issued. When issuing the formal warning you should include all misconduct in a single warning, rather than issuing multiple warnings.
The only warnings that a player might not know they received would be LTAP or LTARP.