How goofy is this?

You hear what you hear most of the time. Sometimes you hear what you want to hear.

I'll give it a 5.76 on the Goofy Scale.

Compared to some of the crazy stuff we do in this hobby I'd say you're barely a "1" on the audiophile goofy scale of 1-10.

Doesn't register on the goofy scale for me.

Anytime something sounds different, there is a 50/50 chance of it also sounding better versus worse for whatever reason. Those are the only two choices.

Call it audio Karma if you like.

IMHO I think that this is not totally goofy. What you are hearing could be an improvement in sonics. The parallel/shot-gun biwiring does present a different impedance of the speaker to the power amp compared to a single run speaker cable & that alone can be better off for the amplifier. Often manuf will encourage biwiring for their particular speaker models.
What you should do is listening long-term to your music that you are very familiar with. You know what it used to sound like & now you are hearing a new sound. Is the new sound still better few days down the road? 1 week later? 1 month later?