Hi mate,
As far as I remember the SF260F has got an uprated engine and a fuel injection system, but all the rest is as per "main project", landing gear system included.
I don't think there are any SF260F flying in Italy at the moment, and anyway, as Ramones already said, I'm not aware of any potential defect regarding the landing gear system on model A to C (should be the same landing gear system as model F).
Could be than an issue directly connected with your own model? pretty sure the factory can help you out if you contact them as Nick suggested.