heliski22, no problems with winglets coming loose here, but have had a nav light on the winglet stop working due to the wiring breaking. When we pulled it apart we found that Agusta had missed out some terminals in the wiring loom back there and had spliced everything together with far too much wire, which then chafed through!
Agusta supplied the correct parts under warranty.
If your winglets are coming loose, do a HUMS aquisition on your tailrotor and see what it says. You might have a 4/rev shaking it back there. Early (heavyweight) tailplanes had iron weights at the tips for harmonics, but the later tailplanes (with nav lights in them) don't.
Also have a look at your top anti-col light base plate (inside the cowling where the wires come out of it). If it is beginning to crack, then that is also a sign of excessive tailrotor vibes.
If after you do a tailrotor vibe run, the HUMS says to do pitchlink and mass, jus do the mass first and then do another run. Quite often it will bring you down to an acceptable vibe level, and it saves you messing around with all the locking on the pitchlinks.
Not sure if you have HUMS or not, personally I like it, especially the RTB side of it.