Visconti Homo Sapiens Bronze Age oversized lava fountain pen leaking at section end

My Visconti Homo Sapiens Bronze Age oversized lava fountain pen has recently started to leak ink which gets on my fingers at the forward end of the section-- no burping just ink around the finger surface edge of the section. I've had this pen for over 2 years now and I like it very much since the EF nib is very good (fortunately!). Since I don't own the special Visconti tool to unscrew the nib-feed nit, I, now and then, use my fingers to unscrew the nib-feed housing unit doing this to use a blunt tipped syringe to squirt water into the ink reservoir in the barrel. I don't know if the nib-feed housing unit removals I've done have led to this recently started leaking. I think there's a tiny O-ring at the lower threaded barrel-end of the plastic nib-feed housing unit. Could that tiny O-ring be worn out? Could silicone grease solve this problem but if you say "Yes, use that grease", where on the plastic nib-feed housing unit would I smear some of it on?

I had the same issue. I tried silicone grease on the threads and o-ring (just a little bit) and it didn't completely resolve the issue. I found that unscrewing the nib/feed unit half a turn solved the problem. I think on some of the pens the threads were tapped too deep and screwing the unit in until it bottoms out places the o-ring seal beyond its actual sealing surface. Haven't had a leak since then. I do the same thing in my other HS models and haven't had leaks in them either.

Thanks Scooby921 ! I'll try what you did to solve the minor leakage.