When Harm and Bud are in the conference interviewing the son-in-law you can see that Harm is wearing two different types of shoulder boards.
One member of the court is an enlisted man. Per UCMJ article 25 and Manual For Courts Martial rule 503, no enlisted personnel may serve as members of the court in the court martial of a commissioned officer.
When Harm first meets Chaddock in prison, he refers to him as Captain but being convicted and imprisoned he would have been stripped of rank and as a matter of policy no one imprisoned is referred to by former rank. .