Not my job
Disclaimer - not my show. the creator's are doing a good job.
Caitlin looked on as Iris told Barry off about breaking in to DeVoe's home, vaguely curious about what had pushed him to act so rashly - to do something Killer Frost would have done and stop seeing the line that had been so important to him - to both of them for so long.
Once upon a time, she would have waited for a bit, caught him alone and asked him what the matter was. They would have discussed things and she would have talked about her own experiences. They would have shared their feelings and thoughts and the issue would be resolved. But that time was over.
Next week, Barry was getting married to Iris, and it stood to reason that it was now Iris' job to be his confidant and set him straight - to keep him aware of who he is.
Plus, she was no longer an example to be followed - what good would her words do, when she herself had done so much worse in the past?
But that didn't mean she didn't still believe - like she had all those years ago - in Barry, in the Flash, and that the lightning had struck him for a reason.
And she would continue to believe.