Hm.
I'm 95% sure it's a FoxVox issue, because I've successfully used the same keys with other programs, like SRS. I have them as push-to-mute in Discord as well, which also picks them up fine.
My block list is empty.
It seems to me that FoxVox likes some of the keys and doesn't like others, because I've found other ones that also don't work: 5, 10, 11, 15, 23.
It's so weird! For instance, IFF in, IFF out and VHF all work, but UHF does not and pushing in that switch does not. Speed brake close and neutral work, but deploy does not (and all of those definitely work, both in DCS and FalconBMS!)
Ok, I've posted an update to attempt to fix the issue. Unfortunately I don't have any hardware to test, so I'm relying on you to let me know if it resolves the issue. Also, I've added in a feature with the Push-to-Talk settings that let you specify 'Any Key' to allow any of the bound keys to activate PTT rather than all. Let me know how it goes!