I'm going to chime in here with a couple of thoughts. My Ruger MarkII Stainless Target never did anything like that to me. Field stripping it stinks, but the thing always works, and has from day one. (smug mode off) On the topic of .22 for defense, absolutely not. I've been shot with a .22. The clue was the hole in my clothes. Based on that, I think you'd need perfect shot placement to get quick stoppage of an assailant. You try managing that under severe stress. I want to do the best I can to shoot center of body mass, and make large holes, and a good amount of tissue damage. .40 S&W is as small as I'll go for defensive purposes. I'm extremely happy with my M&P .40 FS.
I think the majority of us that are using the M&P22 are either new to shooting or, like myself, new to pistols. Or just using it as a trainer/plinking firearm. I ain't gonna EDC it. I have alot of confidence in shooting a long gun in a high stress situation. However, I am new to pistol shooting and would like a gun to train on to graduate to a .40 S&W, .357 Sig, or .45 ACP. M&P or M&P shield would be my choice.
I do also think that with a .22 LR you can slap more rounds on a target faster than you could with any other common pistol cartridge. Especially folks with less experience on a pistol platform. Ain't nothin' wrong with learning on a .22.