Optics can break. Often the adjustments stop working, but sometime you see the reticle cant after the optic breaks. I don’t recall this brand of this optic, but is was old and cheap. More expensive optics tend to break less, and NCStar optics seem to break the most out at my range.
Cheep guns often have more issues then more expensive guns. For example this cheap revolver not only would randomly lock up, the barrel was loose in the frame.
Bad ammo can cause issues. Some RWS .357 ammo was popping primers in a S&W revolver causing the action to lock up. This happened more than once from one box of RWS ammo in this revolver.
Bad ammo can be disasterious in firearms.
In this case, a bad round of Georgia Arms 9mm ammunition blew out in an old Glock 17. The frame of the pistol was cracked, fortunately the shooter was unharmed.
There is always the looming chance of failure. Mitigate this by buying quality firearms, accessories, and ammunition to prevent problems. Lastly, have a back up plan. For example, if your going to the range for fun or training, bring more than one gun, 1 mag, etc. That way should there be an issue with a firearm, or mag, etc, you can keep shooting. Don’t forget spare batteries.