Personally I *don't think* I had this issue until I changed my VON Volume setting.
A friend was explaining how everyone's mic's were so loud, I was trying to help him figure it out & explained mine sounded normal.
He kept insisting that I change my VON Volume setting to 100% then back and compare... After I did everyone became obscenely loud, and I couldn't control their volume.
Can't be 100% sure, but it seems not everyone has this issue immediately. However my friend and a few other in this server (C4G US #2) noticed it as soon as they started playing. I asked my friend and he said he did not change VON settings prior to noticing the issue. Friend is on Windows 10.
I checked my "x.arma3profile" during changing it, and it DOES update the value in here. Seemingly not using this value anymore.
**Update + Temporary solution**
Thanks to @Terox for figuring out that VON volume is tied to Effects volume. What this means is; Whatever you have your "Effects" volume set to, your VON volume will be the same.
If you're used to playing with low Effects volume, it shouldn't be too bad. However if you're used to playing with high Effects volume, it could be very bad.
For now, the only solutions are;
Play with low effects volume & VON enabled.
Play with high effects volume & VON disabled.