Gearswap changing equipment real quick

So this is more a general question.  When I use the aftercast function of spellcast it seems to swap my gear real quick.  It seems so quick I'm wondering if the gear swap is having any effect at all.  Is this normal?  For instance for SMN I'm using this:

    if spell.type == "BloodPactRage" then
        equip (sets.bpr)
            if spell.element == "Fire" or spell.element == "Ice" or spell.element == "Wind" or spell.element == "Earth" or spell.element == "Water" or spell.element == "Thunder" or spell.element == "Dark" or spell.element == "Light" then
                equip (sets.bpmdg)
            end
        function aftercast()
            equip (sets.smn)
        end
    end

When I use a rage blood pact I blink out, and if I have the equipment interface open I see the gear swap to my blood pact set then back to my base smn set, but the blood pact set is on there for a fraction of a second.  Is this normal? Or do I have something set wrong?

I should clarify that function precast(spell) is included above this, this is just one part in the precast function.

First of all, you should be aware of the distinction between precast and pet_precast, the latter of which is what you will want to use for BPs (except for enmity gear, which is actually relevant at the actual precast time).

Second, you can use //gs showswaps to enable display of what gear changes, so you can verify if everything swaps correctly. But yes, precast should always swap correctly, even if it's really fast.

Third, the function aftercast() thing you got there does nothing, it won't equip any gear. The aftercast function cannot be defined inside the precast function or it won't have any effect.

Fourth, why are you checking for every element? You can omit that check entirely.

Gotcha, thank you for all the help Arcon!  I had the line to check for the elements hoping to use the eminent staff and Hagondes feet for the combined +50 pet mab for BPs that are magic damage based, but avoiding that swap for the physical damage ones.  Though looking at the resources it seems like all the BPs are assigned to an element, even the physical ones :/

Yeah, just like JAs have an element and non-magical WS. We currently have no way to distinguish magic from physical BPs, because that data is not in the DAT files. We would have to add it manually at some point.