In MoP the faction Vendors offer a commendation that boosts Rep gains account wide once a single character gains Revered. This item is non refundable and unusable if you have already applied it once in the passed. Any reputation so boosted has always been indicated by a small arrow next to the rep progress bar on the reputations tab but now that arrow is gone and no other icon has taken its place. this means that you have no way of knowing if you applied the commendation some time in the passed 8 years and that’s a problem when the commendation its self gives no hint, and it costs more gold than you can make in 2 days of questing in Pandaria.
Am having the same issue.
Please fix ASAP.
Yes, me too. There is absolutely no way to tell if a commendation has already been applied other than buying it and then finding out you can’t use it. Please fix with some sort of indicator either in the character rep tab or on the item itself with an “already known” tag. Kind of important now that you can fully level in MoP!
Me three. I’m gonna say “not fixed for Dragonflight” then. 
This wouldn’t be such an issue if the Commendations were refundable. Simple solution Blizzard, please~!