Actually, the Fare Rules say that the $125 fee applies only to re-routes. A Re-Issue for technical reasons is not a re-routing.
Of course, I just wanted to explain why this issue happens quite frequently. The problem is that the rules only say that date changes leading to a re-booking/re-validation are free.
So if the date change is not leading to a re-validation but to a re-issue then some agents use this as an invitation to charge as in their mind a re-issue is $125.