As the title says, I think there's a bug after the update last Jan. 20, 2020.. Combat Mode is ON for me because that's where I'm used to in switching skills. Before the update, as I press the button to switch skills, it will switch without a problem. But after the update it won't.... kind of, it will still switch though but after many tries of pressing the button to switch. This is problem in Boss Rush and Ancient Ruins when I'm not Auto'ing it... especially in PVP.

Here's a video by the way...

Have the same issue. Combat mode ON or OFF it doesn't matter.
It seems that in auto mode, when the deck is switching by itself, there is a delay while you can't change manually the deck. This is really annoying ...

I see. That's a good observation. Thanks for the info!

Hoping that they fix this really soon.