A/B testing seems completely unnecessary and shouldn't be used if it is going to give advantage to a number of players. It's even stated that your A/B testing won't cause any advantage but giving some players rewards and other not, is a clear imbalance of rewards.
Using the excuse it's an industry wide standard doesn't mean it should be used and if it is, should only be used when there is no benefits gained by one group over another. Clearly one group will gain advantage by this feature . Behaviours could easily be tested by giving the feature to one server and comparing it to another similar server.
Will you provide compensation to those losing out? If not this should be removed asap and thought about some more before implementation.