PC weapon cycle bug

I noticed as I cycle through my (2 and now 3) weapons, the last one cycles twice before going back to the 1st weapon.
Beginning of a every map my FPS and hard drive are sluggish… For a few seconds.
Also, during certain fights and when I zoom in.
And when are the bad guys supposed to load in… A couple times they loaded directly near me. It was on the way back from finishing Head Case Side Mission, as I came down to the trailer flight scene, the bad guys appeared all around me.
I haven’t really found a reason to use a sniper rifle yet, since the bad guys don’t pre-load or whatever they are suppose to do.