Say, hypothetically, you have a coworker you work well with, but get in heated political arguments with as well. This only happens maybe once a quarter, so they rarely even register as hiccups in your working relationship.

Say, now, that during one of these arguments you recognize a cognitive bias in the coworker's argumentation. The likelihood is high that they are falling into the bias in other contexts (you might argue that it seems more likely that they can clearly compartmentalize and only display thoughts which show evidence of the bias when they are heated - so, say for the sake of the argument that you can now remember an obvious example from daily work where you have seen them lean on the bias).

Here's my dilemma: since you now have evidence they are employing a cognitive bias, do you have a moral (or even, team-based or business) obligation to point out the bias to them? If yes: How much residual damage to the working relationship would you tolerate before changing your answer (again, for the sake of the argument, presume not that you imagine they would take offense - instead, you know yourself well enough to be aware that you would be so additionally disappointed or even angry at them if they ignored you or showed no receptivity to your bringing up the bias with them that you would no longer tolerate working with them)?