That stinks. We bought a PK380 a few weeks ago. Have about 150 rounds through it. First few rounds (I did not clean it before taking to the range) had several misfires. Turns out the slide was not returning all the way forward. Cleaned it real good and haven't had any issue since.
I read somewhere about some good slide grease, but now I can't remember what it is. Might try to find some just in case. My PPS did the same thing but I have since cleaned it really good too.
Good information to know. I've had a pk380 for a couple years now. I dont shoot it much though. I use it as a backup weapon on my ankle. It gets really dusty and dirty but no malfunctions yet. I should probably go out to the range and run a few boxes through it just to make sure.