definitely set to SWITCH
I'm afraid I'm mystified. If you set EXTIP to BOTH, you lose TIP, and both ring and tip/ring show as RNG. But this is not what you are seeing. I tried EXPTIP set to SWITCH on 5.0.1(3) on my H9 and it works fine.
So, back to my previous note. Try and find both a different switch and a different cable and see if that changes anything.
If not, you should contact email@example.com, referencing this post, and send in your pedal, switch and cable. Sorry – can't see another way – hopefully someone else has a better idea.