KJW Glock 27 firing issue

[kar120c]

My KJW G27 has this issue: wihout the slide on firing is ok. with slide it fires only if I apply strenght to the slide form left to right otherwise pulling the trigger doesn't active the hammer
I cheked and lubed everything but I can't find a solution

[Ranger11]

there's a reset nub on the sides of the slide, the one on the right (if you hold it normally) is the one that does that. Check it, if not dig open the hammer assembly and look for broken parts