Try LALT+NUM7 or LCTRL+NUM7. Just to be sure it's not assigned anywhere else. And assign it temporarily to any mouse key, so you will be sure that keys are pressed simultaneously.
For me it works like that:
https://www.youtube.com/watch?v=NA4rggDCQcE

In T187199#2719147, @kawalec wrote:

@Ponezun
Paste a screenshot of your key bindings here, please.

@Ponezun
Paste a screenshot of your key bindings here, please.

In T187199#2718865, @kawalec wrote:

OK. Look at the screenshot below. I assigned my "Switch weapon optics" to M5 (mouse button number 5). And I am sure that it's the only key bindings for this button. It is possible that the same combination of keys you are using at the moment for "Switch weapon optics" is used by some other action. So assign some unique combination like LALT+LCTRL+LSHIFT+9 to "Switch weapon optics" and see if it works. If it does, it means you had the same keys binded with different actions. If id doesn't work, problem may be elsewhere.

In T187245#2719059, @ookexoo wrote:

Add -forceUpdate to launch params

Geez please disregard and delete. It was a coincidence that my TrackIR LEDs started malfunctioning the same day of the updates. Sorry

Add -forceUpdate to launch params

Great guys: I reported this almost two month ago for the experimental and now you released the version with exactly this problem. wtf

please fix this, i like to use FSR and get more frames but with that blury gear menu its so ugly

OK. Look at the screenshot below. I assigned my "Switch weapon optics" to M5 (mouse button number 5). And I am sure that it's the only key bindings for this button. It is possible that the same combination of keys you are using at the moment for "Switch weapon optics" is used by some other action. So assign some unique combination like LALT+LCTRL+LSHIFT+9 to "Switch weapon optics" and see if it works. If it does, it means you had the same keys binded with different actions. If id doesn't work, problem may be elsewhere.

Appears fixed in 1.3.0.18.

In T187232#2718638, @PR9INICHEK wrote:

Oh, I was looking for a ticket only on PC.

You can then close mine in favor of the one that was created earlier

In T187199#2718467, @kawalec wrote:

So there is the same key/key combination assigned to two different actions. Check it all.

Oh, I was looking for a ticket only on PC.

Duplicate of T177354

Added: Server Join Queue

So there is the same key/key combination assigned to two different actions. Check it all.

In T187199#2718232, @kawalec wrote:

Check the key bindings, there are some changes, so maybe that's the cause. For me it works exactly as previously.

This issue has officially been resolved with update 1.2.1.169, as you now speak over direct communications by tapping LB to toggle direct communication, and hold LB to talk over radio.

This is still causing crashes as of game stable version 1.2.1.169, any updates?

Completely agree with both of the comments above. There is very little incentive for server owners and admins to carry on hosting. Server costs are huge and a VIP system (as in other games) is absolutely essential.

And it's still not fixed in 12th December update.

damn it. that explains some of the WTF moments i've had in the game over the last few months where i thought to myself “how the hell does the opponent see me”. too bad, too bad...

First Person Perspective(1PP) should the normal case, not the exception in a military simulator.

I completely agree with this request and want to emphasize its importance for server admins and communities alike. The introduction of the queue system is a welcome improvement, but the lack of VIP queue functionality creates significant challenges for server management and sustainability.

Check the key bindings, there are some changes, so maybe that's the cause. For me it works exactly as previously.

Resolved for 1.2.1.169

This video gives a better idea of this issue, recorded on version 1.2.1.169. My fps is around 30 or so