Retraining units in city with casse "field of games" causes extra unit upgrades

[Ferromancer]

Build a "field of games" in a Casse city. Train a unit, it gets an experience bonus (as expected). Send the unit into combat, the unit doesn't receive experience, but loses units. Retrain the same unit in that Casse city, and it will receive another experience chevron after training. The building should only ensure that units have a minimum of one experience chevron.

EDIT: Forgot to mention, playing EB 81a in BI with Hull's CTD fix.