6L80e TU/TD: Downshifting twice for a single signal

Before I get too deep into troubleshooting I want to see if someone has experience with this problem.

I have hardwired the TU/TD signal to my 6L80e and it worked well for a few months (following the wiring info on this site). I have been adjusting shift points to improve shift feel (along with CT downshift elements) and noticed that in TU/TD mode it will downshift twice when pressed only once.

I can move to manual mode and it stays in the gear just fine. I can also upshift and it goes up one gear. When I signal the downshift it shifts down a gear and then almost immediately shifts down again. My first thought is that the switch is faulty but this behavior aligns with other transmission tune changes I've made so I suspect I inadvertently changed something.

Tune attached.

Thanks!

So if you really suspect it's something in the tune file, go back to a tune file from before it acted weird and see if it goes back to working the way it used to! And then add back in the changes between then & now one at a time until it breaks again!

Thanks! I should have thought of that first. I noticed one change was the enablement of "Mountain Mode" so I tried just disabling that but without success. I'll try to just reload an old trans tune and see if the behavior goes away.