Cant shoot after reload

Happened few times today with IAR LMG with the mag well upgrade that lets you to reload while ADS. Right after normal reload, I ASD and try to shoot, but nothing happens and I just stood there like an idiot while the enemy killed me. On a 3rd time I had time to stop ADS and as soon as I released aim I could start hip firing.

Also had more than average number of shots not registering on that same game (example got 3-4 hit markers on an enemy, then a team mate killed it and I didn't get any assist or suppression).

Not sure if these are related, maybe something like server lag, net code etc. (my ping is usually one the low side around 15-25ms, so it's not that).