I think KelTecs just get homesick every now and then.
Seriously though, can you describe your light strike?
Did it feel like you got a good trigger stroke, but no ignition?
Or, did it feel like the trigger kind of "short stroked", causing the hammer to strike without going back all the way?
I've seen both types of failures.
My wife's gun was getting a good hammer strike, but no ignition, on occasion.
KelTech sent a new hammer spring that fixed the problem, but now the trigger on her gun is almost as bad as a KelTec P11.
On my gun, and my brother's gun, we would occasionally get a "short stroke" on the trigger.
The hammer would fall, but you just knew that the trigger hadn't been pulled back far enough.
A new hammer block will usually fix that.
Maybe a new hammer.
Finally, have you tried other ammo?
It may be that your gun just doesn't like a particular brand.
That is not unusual.
As far as upgrades, if you have a recent serial number, you should have all the latest fixes.
If you send it in, they will prob. replace hammer, hammer block, hammer spring, and maybe a few other things.
Hope this helps.