Since a week and a half, after the DCS 2.5.5.34864 Open Beta version update.
Only bindings I changed where labels on/off, and I mapped those on my keyboard. No controls crossed otherwise, was the first thing I checked. Also I don't have the HMD knob bindings assigned, since I don't use the JHMCS not that often.
And I can't turn it off when it happens, it keeps switching back on after a few seconds. Weird it doesn't do that when you take control. I'll check my bindings again tomorrow, just to be sure it actually isn't a controls crossing. :)