Quoting TV-Tropes, this is a trope related, usually, to long running franchises, who originally had unusual concepts or ideas, later abandoned (think of a prototype of a work that later becomes a well-established series)
- Before "Pokearth" was a thing, the Pokemon series was actually set in "our" world. Correct me If I'm wrong, but after Gen.3 they stopped mentioning real-life places (like Lt. Surge being from USA. Later it was "retconned" and he's actually from a sort of USA-equivalent state and, later, was established to be from Kanto region)
- I suppose it can count: Dynasty Warriors, originally, was basically a fighting game (think of Soul Calibur), but they shifted from the genre with the second entry. Actually, I think that Koei didn't acknowledged this first game as a part of the Dynasty Warriors series (but, to an extent, the entries that came after that game were influenced by the first one), while on Western releases iirc it's a bit different. We have a sort of number discrepancy, in fact our DW3 is their "Shin Musou 2" (second installment, basically, of a new "series", unrelated to the first fighting game).
- I'm not familiar with the original dub, but in the original pitch from Phineas and Ferb, Phineas sounded a bit different. His voice actor was still trying to "get into" the character and from what I've read online his characterization was different (in fact, there are some traits of him that were never "added" into the actual pilot/series). An example is his sarcastic tone to Isabella when she points out that they can't "build a rollercoster in their garden". There is also Candace saying "Their butts are mine" to their mom while trying to bust them
- Persona 1/2. If you compare the first two entries with the modern "formula" we got after P3, the first two games were a totally different thing. Just to have a glimpse of the differences: social links were absent. The game was basically a huge dungeon crawler, and all the characters were the ones that later will be called "Wild Cards" (so they used multiple/different Personas). Also obtaining new Personas was a pain, you needed to "negotiate" with them, while doing a sort of ritual to Philemon.
I suppose this also counts for Shin Megami itself. Like, originally, the "Demons" couldn't level up or inherit new skills, while the first concept of the Personas was called "Guardian" and it was a bit different from what was introduced later (basically you had, for example, Tajikarao, who acted like a sort of Persona, with spells/skills. You had to fill this "Guardian Gauge", and from this, you could've gained new "Guardians", depending on your level, after the death of your character)