Tap right click to see if it frees you from this state, I've noticed that right click puts you at ready, when at ready you are moving slower to keep your "aim" steady.

Thanks, will give that a try!
If that is the case I would suggest removing that function when empty handed.

I've also been frustrated by not being able to run and found it was the Optics key binding to short press Sec Mouse button being accidentally pressed.

As stated this slows you to keep aim steady when you have a weapon, but does it regardless of whether you have a weapon.

This is NOT the same as the long press (hold) Sec Mouse button to zoom.

Just tried it and it seems indeed that case.
I will change the ticket with the updated issue.

Updated issue from walk/run toggle to sec mb.

I actually remember this happening in the mod as well.

Old ARMA 2 / OA bug that needs fixing in standalone.

It would be great if this got fixed, annoying when you have melee weapon or nothing at all in your hands and you can enter aim-mode, seems like something that would be easy to change (if no gun in hands, single-click right mouse should do nothing).

This bug doesn´t happend randomly. It happens everytime you right-click.

The right click and space bar system is a bit broken. It would probably be better not to have two separate modes, but one mode with multiple steps/variations instead.

A quick fix could be to have a small icon show which settings are active, because in some cases/some stances/some items you don't see any difference between optic/not optics and attack/not attack. Or it should revert to "normal" automatically when switching weapons/items, and/or it shouldn't be possible to enter "optics" with e.g. fists...

Agreed. This needs to be changed.

It seems that even if you do not have a weapon in your hands - your character will think he is looking down the sight of an invisible gun, which in turn, forces you to walk.