I mainly use elemental toggles for the primary.
Lately, I have noticed that it will turn itself off.
Here are the AA enhancements that I have:
All 6 of the core
energy of the wild (3)
force arrows (1)
paralyzing arrows (1)
Imp. Ele. arrows
AA tree is accessed through Helf
Obviously I am still testing and trying to figure out what is making the primary imbue click off, but wondering if others are seeing the same thing and if there is a work around