They said in a recent interview that they have gone to great lengths to make Cyrodiil in TESO as close to Cryrodiil in Oblivion as they can, even going as far at the have points of interest from oblivion be in basically in the same place in TESO, and since they have Bethesda backing them on this project and Bethesda Lore Masters telling them if its ok lore wise or not then im sure everything is just fine lore wise.
Well, apparently, the CHIM Talos used to get rid of the jungle, works retroactively as well, so it not only changes the present and the future but also the past. So it makes it so that Cyrodiil was NEVER a jungle in the first place. It's basically a fun lore-based way to ret-con stuff, haha.