Fist of War and Rolling Slam AoE size issue

Putting Fist of War into rolling slam seems to incorrectly alter its AoE size in conjunction with other area size gems. If you run Rolling Slam with Expanse and Magnify then it becomes huge, but if you also pop in a Fist of War at the end it reverts to its base size and becomes tiny again.

It seems to even reduce the size of the second slam if you only put Fist of War in.

I have about 62% increased Area of Effect from passives and I am using a 2h mace.