Thanks Lukas...
The suggested "workaround" is something I wrote in a
separate thread, and after re-reading it, I just wanted to clarify...
On the last day of the postseason, I uncheck the "Import Real Rookies" box, advance one day to start the offseason (which is when rookies typically import onto their real life teams if that option is selected), and then once I'm in the offseason, I re-check the "Import Real Rookies" box so that the rookies will import when my draft comes by.
Ever since I started making this part of my yearly routine, I haven't seen any players who retired "early" in my alternate history re-appear in the DFA of teams they played for in real life.
But if you don't do a draft for your real rookies and instead place them on their real life teams, this won't help. Sure, you'll prevent the retirees from reappearing on their real team's DFA, but you'll prevent the rookies from appearing there too.
I always thought this issue was due to my league being an older one that had imported across several versions and perhaps used an older player ID format than what is currently used. But others have claimed they see the same issues in their leagues, even if it's one they started in the latest version.
Hope this workaround is helpful to some!