Scouring Winds and Incinerate

This might not be a bug but it doesn't feel right.
The Stormweaver Ascendancy node Scouring Winds does not provide the 20% additional resistance lowering effect to exposure applied by Incinerate.
Incinerate does say that it applies stacking fire exposure up to a maximum of 50% but increased fire exposure effect increases that maximum (50% increased fire exposure effect brings it up to 75% exposure at full stacks), so it doesn't make sense to me that the ascendancy node shouldn't also work.
Thanks,
Frosty.