I just picked up one of the Type 56 Spikers from PSA and noticed that when attempting to deploy the bayonet, it barely locks in place and is very difficult both to deploy and to stow.
The front bayonet lug has very little engagement, as shown below.
Additionally, when deploying or folding the bayonet, it gets jammed right here (where the pen is pointing). I can push past the jam with force, but it takes two hands - one to raise the locking collar and the other to push on the blade of the bayonet to gain enough leverage.
Is this normal operation? Looking at YouTube videos of the rifle, it looks like they have more engagement on the front lug and no interference when deploying the bayonet. The screenshot below is from Forgotten Weapons. It still doesn't engage all the way, but it appears more secure. With mine, I'd be worried about the bayonet slipping off of the front lug if it were used roughly.