Not as much predicated on learning their lessons once it is given to them and more paying heed to lessons they reached themselves. Pinkie Pie had reached the conclusion on her own and as such the lesson was a realization, an epiphany, earned by herself. These lessons often have greater impact on the individual, and while new situations may challenge these lessons, causing characters to seemingly relapse, this is often an evolution of the lesson itself, adapting for the new, unforeseen circumstance.
For a hypothetical example if I have a friend who I give a playful nickname. Despite the several signs saying he doesn't like the nickname, I continue to call him by such, until I eventually catch. and realize I should stop. I may slip up in the future, calling him the nickname, but the lesson learned would still be in my mind, helping me to overcome my fault, and maybe eventually learn my lesson completely.
In other words the lesson Pinkie Pie reached in "Pinkie Pride" would likely, not certainly, be a factor of her actions with in "Filli Vanilli". I don't find otherwise to be impossible, or for Pinkie Pie to be even acting out of character in relation to former episodes, but it raises the question of "if so, then why?". Why did the lesson she reached in "Pinkie Pride" not factor into her rationale in "Filli Vanilli"?
And while not a strict continuity, there is an implied continuity, which helps us perceive an episode order that is reinforced by the air dates. This is especially apparent within season 4, where episodes often reference former episodes, even the former episodes of this latest season. Again, this isn't a certainty, but the presentation does exist. I do agree though, these particular two episodes could be switched about without affecting the continuity of the show, beyond how it would present Pinkie Pie's actions within "Filli Vanilli". As it appeared by the air dates, one happened after the other, but it doesn't necessarily mean that's the case.
Would people have been annoyed with Pinkie Pie in either case? Yeah, can't imagine otherwise, she made Fluttershy cry for Celestia's sake, but the question is really aimed at those who were annoyed by her actions in "Filli Vanilli", and felt it too contrary to what she had leaned in "Pinkie Pride".