I've maxed out the passive skill "Pet mastery" and... even if it states "reduced pet travel time by 80%" it's actually to the point that in the moment i send my pet to town and goes offscreen it comes back right away, is it a glitch or what ?

And yes, he comes back with the items being sold too.

Far out!

I would assume that's no glitch. I've never actually put any points into anything pet related but given how far out parts of that game are it doesn't surprise me at all. It would be a glitch if he didn't sell anything. Wait till you get to Torchlight 2 when you can give your pet shopping lists and they can go out and buy stuff for you.

I already have Torchlight II on Steam but i want it on GOG too because the Steam version... got "ruined" by the "Steam workshop" and filled up with stuff that makes it look more like Team Fortress 2... I really pray to have TL II on GOG >.<

Maybe you have items that boost your Pet Mastery even further?

i have this issue too, and my skill pet mastery not maxed yet it's just level 4! and an armor that increase my minion speed.

I don't think it is a glitch. The values are probably rounded up or something in the code such that the timer has no time to display the time for your pet before it is back again.

Haven't maxed out the minion speed as well but an item gave me instant 80% reduction in going to town time.

This happens to me as well, but it's the Epic Zoromun's Fancy belt that is doing it.
80% Decreased Pet Town Travel Time
+20% Pet & Minion Speed.