ARRRRGH!!!! Please! Don't make me say it again!
OK, I'll leave alone the subject of whether synthetics are better than boring, stone age, oils and whether a boring, stone age engine needs anything better but I will say, categorically, that if you swap from a Non Synth to a full synth after any period of time using one or the other you greatly increaee your chance of leaks. I'm not saying anything more.
On the subject of the filter? Surely you had it changed, and the sump dropped as part of the first service? This should exclude Guiseppe the Wog, who is guilty of lots of crap with Guzzis, from the equation.
The fact is even the service book sez that the sump should be dropped for the forst filter change to *examine* the screen. While the one or two *Broad Sump* odels I've done this to have been OK tales are leigion of swarf and crud in the sump, especially since Aprilia waved their magic wand over Mandello.
As Al sez, don't worry, it's fixable, probably a lot cheaper than *factory* if you use a bit of common sense. But Don't risk fart arseing about and not doing the job properly.
When installing filters the gasket should be oiled and the filter put on *hand tight* no more. If you put it on dry and tighten it up till you fart you've got no-one to blame but yourself if the bastard won't come off next time!
Having grown up with earlier bikes where you had to remove the sump to get at the filter, (Which I never found a big chore.) and the docuented occurence of oil starvation caused by the new pick-up system. I find this new fangled whining about filters silly! Good God man! Grow up and take your sump off like true 'Leather-clad God of Speed' rather than whining about your leaky tube!!!!! Are you mouse? Or Moto Guzzi rider!!!!!
Pete