I mean the HUD would be enabled by default, just not with a hotkey to toggle it unless manually bound. And remember, shift has to be pressed in combination with F3. I didn't see that being hit accidentally. Regardless, changing it to shift + F12 by default may be the way to go.
However, there's a decent chance the problem is actually due to the program thinking the HUD 'Enable' variable is getting unset, even if the key isn't being pressed. 0.10.2.6 will have changes in it to hopefully fix that problem.