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The episodes move to digital painting late Jhoto and 4kids edits were a little rough compared to the Japanese. Since this is something you're listening to on the side it's probably not worth going after the subs for your situation. Until roughly 40 episodes in (The March of the Eggsecutor squad) they were aired daily in syndication before Kids WB picked them up. Some rips of "The Problem With Paras" might even have a thing saying "You can only catch Pokemon on Kids WB". By that point however, the Japanese side was well aware of the international appeal of the series and started modifying things for worldwide audiences which resulted in far fewer changes being needed. In the middle of the Advance season, The Pokemon Company International got back the dubbing rights and changed to the voice actors who continue to this day. While the constantly appearing characters were replaced, by Black and White whatever bad blood was there had vanished and some re-appearing characters (when they were shilling remakes) ended up never having their VAs replaced.
There's a series called Pokemon Chronicles set at the same time as Advance Battle which shows off side characters having adventures. There's also a couple Japanese only episodes early on that were cut for varous reasons and any appearances of Jynx before they made it purple were cut from later DVD releases. There were a couple specials at the end of Diamond & Pearl and Black & White where side characters met in a special episode that also weren't brought over.
Ash has a rather hard reboot just after Diamond and Pearl and again after X&Y. He always dumps his Pokémon off, but in those specific instances he just goes from experienced trainer to derpy kid.
Otherwise just sit back and listen in while working.