Does the ticking correlate to the rev speed of the engine. I.e. The faster you rev the engine, the faster it ticks?
I have had ticking injectors in my alfa before, but that was all the time and liquid moly wouldn't cause that noise to stop, so you can probably rule that out.
As mentioned, to me it sounds like a bit of wear to the cams or on of the tappets that is aggrevated when the engine warms up and everything starts expanding. Moly would shut it up until it starts to wear off and you get more metal to metal contact which could cause the noise you are hearing. But then again, usually tappy cams quiten down after the engine warms up and the oil gets thinner, so i could be wrong...
Get someone to rev the engine when it is warm and making the noise and then see if you can hear what parts of the engine it is coming from. If it is at very high revs you might struggle to hear over the general engine noise.
As suggested i would use the correct, recommended maserati oil to see if that helps first, this could well do the trick. Then if the problem persists look into it a bit further or take it to a specialist.
Sounds like you're not the only one that has given the car a good thrash, but it is a GS after all.
What kind of mileage has it covered?
It doesn't sound like a major problem, so i wouldn't lose any sleep over it. Try the oil first and let us know how you get on...