Until this last patch I was using a mod that was fixing the CTD problem with the Bound Swords that started on the one prior 1.5 . Sadly I can't post the link so you'll have to google search for
General Stats Crash Fix - Bound Weapons Crash Fix
The Following is what I posted to that maker comment page to help others maybe find away to fix this again. I hope this may help you folks as well to find a fix.

Since this mod is currently busted due to the patch this is what I have figured out through trial and error. First note after my very first toon I decided I didn’t wana sit through the first part of helgen so when I got to the riverwood trader I made 4 save files so I could use console commands to change my race and toon looks as I saw fit for later plays. Those saves were made b 4 the patch that broke the bound swords, Also I’m currently on my 2nd play threw. With all this in mind, my 2nd play threw file is clean and was a fresh start as I wanted to try to stormcloaks side of the story. That save was made after the patch that broke the swords.

The 4 temp saves didn’t have this mod running as bug hadn't happen yet and my 2nd play threw had it running. My first play threw save is crashing again with or without the mod (yes we know this I’m just trying to give as much info to help other people.) The 4 temps and the 2nd play threw save work fine with or without the add on.

This is where it gets interesting. I used commands on a temp save to lvl up conjuring just to have the mana pool to test this. Weather it was a tamp save or the 2nd play threw file the outcome was the same, Left and right solo casting worked fine but when duel casting both files would only summon a sword in the players literal left hand the only way to get the swords to appear in both hands was to channel left and right so it wasn't a duel cast. Now this is important to note because if you do a help bound command 3 spells come up. I command learned all 3 one at a time on the broken file and found the 3 ids are set for a reason. 1 spell is tied to left hand, second to the right and the third is most likely the duel cast spell. I'd like to point out that two of the spells are bound to the players hand, Now matter what mouse button you use it only lets you one of the hands. Command learning any 3 on the broken file didn’t fix and that was working with a copy of the broken save that I hand command unlearned the spell saved quit and reloaded. The only other tests I can think of to see if the duel casting only summons a left sword is to start a fresh game that doesn’t have the add-on loaded and see if it still happens. If it does we may be 1 step closer to the true problem.

Update: Starting with a fresh game and no mods of any kind I command advskill of conjuration, command gave myself the spell tome of bound sword. Learned the spell duel charged it. Both appeared, took points in conjure to get empowered duel cast and it only summoned a sword in the left hand. So I'm guessing whatever the issue is its laying somewhere in empowered duel cast and the third bound spell, as after u take the perk there's no way to summon swords in both hands under the overcharge affect. A.k.a hitting both buttons at the same time vs. one after the other. Even hitting both together and letting one go didn't matter which ended with a sword in the toon's left hand.