Some examples of where an Oath of the Crown Paladin can break their Oath is when you deceive the Blue Jay in the Emerald Grove in Act 1, punishing Madeline through He Who Was in BG3's Act 2, or ...

But oaths that explicitly reference the targeted behavior and spell out the rules of how to behave may make it harder to “wriggle out” of being honest without damaging one’s self-image.