I've seen this happen several times in ootp25 as well- occasionally young guys peak early, that's fine, but it does seem like an error somewhere is making it very commonplace. Especially noticeable with pitchers losing velo in their early/mid twenties without an injury. Again a thing that happens! But happening weirdly regularly!
This guy was BRIEFLY elite, in a league with scouting off, then he turned 24: