My gen4 26, purchased last month, had issues going back into battery when racking the slide. I called Glock and they sent me a new recoil spring assembly without any nudging on my part.
Inspecting the old RSA showed no visible problems. The new RSA corrected the battery issue, but I have yet to shoot with it.
This may have nothing to do with your specific issue, but thought I would mention it just in case.