No commendations.

[Chocolys]

Assuming they were not inexperimented to the dungeon and caught up in the mechanics, It has not much to do with the character level but about the player motivation to play their class with at least a moderate efficiency.

There can also be another reason, they might have "easy-leveled" the classes they were playing with you, such as for example with Fates or Daily hunt marks, both who can kinda be completed by spamming random skills. And then decided to try that class in a dungeon

As for the commendations, sometimes it's kind of random, even more when it's with Full Party (8) where it's hard to decide who to give your commendation to unless someone particularily standed out.
I guess that's why Tanks especially and Healers to a less extent have it easier with it, because they naturally stands out with their respective role.