So I just looted the Sciropescire treasure horde and got nothing, so I went and looked it up. I was supposed to get the Vidarr head tattoo, which I apparently didn't get because I already had it.

Normally no big deal, but with the general buggy-ness of this game, I'm worried I previously got the tattoo when I was supposed to get something else, so I'll end up missing something.

Googling doesn't seem to bring up anything useful, so I was hoping someone here might be able to ease my mind.

i think somebody have this issue before but this is my latest problem. i think i have maxed out every skills in the skills tree and i even double and triple check every of the skills everything were already maxed out but why would i have one more skills points? when i up lvl more i gain the master skill point now i try use the auto assign skills as well but nothing happen. my current power was 535

So a few things ill point out that you missed followed by things you got right.
Valhalla Cons.
You changed the birds ability to lock in and marker, huge deal guys.
You took away the ability to slaughter people and fight Mercs, another gigantic step backwards.
It seems like you messed up the climbing? As in you get stuck on stupid wayyyy more in valhalla.
You took away the map description (when you hover over something and it tells you what it is) this is Super annoying because many of the icons don't actually make sense.
The limited variety of weapons makes the game a bit meh.
Those are my complaints, please FIX!
Valhalla pros added that are not in oddysy.
The ability to reapply skill points are spot on, great job.

I hope this helps your ability to bring the game to greatness but honestly I think many of us are wondering how you made a smaller game than Oddysy and yet you made it worse....
You can redeem yourselves if you fix the things listed above along with the bugs.
Thanks.