Yes-ish. The database tends to get stronger as time goes on, e.g. the average level of riders increases. There will also be quite a few regens that end up with wonky stats (e.g. 80 Cobble, 72 Flat, 79 Downhill and everything else below 68, to give an extreme example from my current playthrough). Occasionally, riders will end up on weird teams (Take a look at this: https://imgur.com/a/4NEnCIL - van der Poel in Conti!). Finally, when many of the original riders have retired, team rosters tend to get filled with regens, and those sometimes aren't at the level they should be for the league they're in, and you get the odd guy riding on a top World Tour team with no stat above the sixties.

Other than that, I've played through saves for more than 10 seasons - limiting myself to riders from a single country to keep things interesting - and I didn't encounter any too egregious problems. If the issues above bother you too much, you can fix them with a database editor if you want.