since the 8/1/2017 patch, weapon switch sets are getting overwritten by any random thing you equip. this is a subtle and nasty QoL issue.
if you have in your slots…
rod / dagger
rod / shield
and equip ANYTHING else, one of these 2 sets will be overwritten 
suppose at some point you want to equip audra for casting icewall.
or equip dumbbell for the strength bonus
or any of the random subweapons in the game like the new bubble stick, for fun. well guess what.
now, it WON’T be fun. you’ll be weaponless in your moment of need and die horribly.