(brief and very uncharitable idea about paladins)
Contrary to the what religions might present, gods are just as imperfect as mortals and have a lot of figurative skeletons in their closets, unsavoury deeds toward their peers and exploited mortal lives in their shadows; look at Zeus, for example, and his trail of broken women. But in a certain world (*) where the power of a god is proportional to the number of their followers, such gods would need to keep at least somewhat refined, cleaned up image in the same ways the public personas have to in our own world; a god who is seen as too imperfect is not going to have many following them around. We don't get to know gods' actual myths or deeds (**) because they would spoil the image people have of them and all we get is a few deeds that don't break the facade.
So this is why 1) paladins are not always committed to a single god but rather a side of pantheon, and 2) why they so often operate as charismatic leaders for idea. They are mercenaries to go around and commit required shining/dark deals to boost the public image of divinities, and their divine favours are not powers that gods bestow on their chosen but literally kickbacks and favours that gods pay with to their influencers for their work. If the paladin gets busted, committing something that goes against their image, and, therefore, the image of god(s), they lose the value and thus are discarded. As they are quite often somewhat outsiders to bureaucracy of the church (where many clerics are not public faces, and their misconducts thus can be hushed by the organization), paladins are 3rd party contractors who are all about public deeds, and thus their misconducts cannot be hidden much once committed, or divine powers are recalled due to gods' concern that the next time some LG paladin eats a baby (***) it would be harmful amount of witnesses and words spreads around anyway, so just to be safe better kick away a rotten apple before this happens.
(*) this certain world is most probably/certainly Faerun. I seriously dislike Faerunian model for gods where following a god – any god – is mandatory under a thread of a very painful afterlife, and actual faith is not of any importance for majority of population, which might explain why in a world with actual active deities there is so few casting clerics. And this with a thought that tying in the number of followers to god's power was considered to be a _good_ solution by Ao, because otherwise gods didn't care about mortals much at all.
(**) in many settings gods are just a spreadsheet; we don't have to read their deeds the way we do with actual Earth mythology. Even in abovementioned Faerun there is only a couple of deeds or myths about major divinities and such events mostly fit neatly in their portfolios. This idea plays somewhat on this lack.
(***) or saves a baby if this is a paladin working for some evil powers.