As the title suggests, Lydia still swaps her best bow for her default hunting bow. I've not tested this for any other follower but it doesn't look good regarding that 1.9 states that it was fixed. I also noticed she has problem using a nordic great sword. She sheaths it on her side like a long sword and pulls out an invisible great sword in combat.

She was doing that BEFORE 1.9 it crops up then disappears as far as the bow goes it seems to happen hit and miss with other characters as well, Brylyn seemed to do that, sometimes would use default sometimes advanced it may depend on level of enemies just a guess on my part...

~NS