As all have said you are finding an issue that is self induced. No reason to pull the slide partially back. Pull the slide fully back until it stops, then fully release the slide, letting the recoil springs snap the slide closed. No more issues.

Now if you trying to find another fault, you will likely find with a round chambered, and a full magazine, if you slightly pull or the the slide back or if the slide gets bumped back an 1/8 to 1/4 inch or so, the gun will not go back into battery, by itself. Wrong, it does go back into battery if the trigger is pulled. Just prior to the break point the slide will snap back into battery. This happens because the slide reset groove, in the upper slide, hangs on the trigger bar. When the trigger is pulled, the trigger bar passes this reset groove and releases pressure on the slide, so that the slide goes back into battery, just before the break point. You can test this with a fired casing in the chamber. I don't suggest trying it with a live round, except at the range with the muzzle pointed down range.

Bob