When delivering a sharp palm slap to complete the seating of a loaded magazine into my 365XL, the slide lock/release is usually overwhelmed. The slide closes and chambers a fresh round without my touching the lever or manipulating the slide. This is the desired outcome, of course, but I have never owned a pistol that would jump the slide lock, in this manner. Is this common to the P365XL or does my pistol need some repair? Is this an ill-advised practice with lightweight polymer handguns, in general?

It’s very common among many firearms, I am sure other will chime in, my M&pS do this and so did my Springfield xd among others.

My Glock 48 and P365 will not, no matter how hard I ram a loaded mag in. My P365XL, will if I ram it hard enough. It does throw me off some when doing a speed load. I've been training myself to go ahead and point/fire if it happens and respond accordingly.

When completing transition training from revolvers to semi autos, many years ago, cops were taught the sequence "tap, rack, bang." The "tap" referenced striking the magazine plate with the heel of the hand to fully seat a charged magazine. It was then necessary to "rack" the slide to chamber a round. I don't know if modern instructors still use that slogan? It sounds like sloppy manufacturing tolerances may have rendered it obsolete.