it is not random at all, here's a repro :

• just fire one round
• reload.
• when the magazine is removed, press "F" (firing rate change)
• wait for the end of the reload animation, then press "F" again to come back to the semi firing mode.

the magazine will be removed and the cocking handle will be far back, in semi only. press "F" to go to auto and it will be back to normal!

ah ok sry for my post u was faster with your report xD mayby i should use the search function xD

Also reproducible in conjunction with grenade launchers:

• switch to grenade launcher.
• Reload. While reloading, press 'F' to cycle fire mode
• wait until reload is finished.
• Switching with 'F' will "blink" the magazine.

This is still an actual problem in the latest stable banch 1.54.133741

Cycle through the fire modes while reloading.
You now can move the cocking handle if you simply cycle through the fire modes.

You can experience that issue with following weapons (alphabetical order):

MK18 ABR 7,6 2mm
MX 3GL 6,5 mm
MX 6,5 mm
MXC 6,5 mm
MXM 6,5 mm
MX SW 6,5 mm
Navid 9,3 mm
PDW2000
Sting 9 mm
Vermin SMG .45 ACP
Zafir 7,62 mm

Fixed a long time ago (in a galaxy far, far away…) by locking fire mode change during reload :-)

@Astaroth, I've checked it - it's fixed. Ticket can be closed.