according to some previous posts by xaar who spoke with a GM or GMs and according to them it is a bug. Due to the nature of how this rep was obtained by a 19 or prior to the 4.0 patch it is likely to be unknown if this is actually a bug or if it was an intentional change. The only way to receive rep was by being in party with a higher lvl character as they successfully defeat the boss(s) in the Shartuul event. It has been quite sometime since I did this but I was able to master the event after a number of attempts to maximize the amount of rep received each time I controlled an eligible high lvl toon. The explanation of the change being a bug could of just been the easiest way for the GM to handle the situation. Its pretty sad but the amount of players that this "bug" would affect would be somewhere in the neighborhood of 1 in 1,000,000 players possibly even less. The twink community is a very small sample size of the overall player base. The achievement whores are a very small size of the twink community. The players wanting/seeking Ogri'la exalted are a smaller part of the achievement whores. How quick/solid is the feedback line between EU GMs and the Blizzard Development team? Would this issue even be escalated?
I'm not saying its right but its probably an issue that blizzard can sweep sweep under the rug and still sleep comfortably at night.