Do games on inventory get retro actively region locked?? :s

I sure as hell hope not, buddy
Perhaps it was region locked the whole time? You may be mixing up inventory gifts

Crap! You're right, all my gifts have been retroactively region locked. WTF steam!?
This may cause some major problems for some people that had GAs running right now.

by now it's been there for at least a year but I don't remember the exact time

I'm assuming this was the spare gift copy spawned from a key? Go here and look for ibb & obb (CTRL+F). This will tell you the date.

If this date was later than roughly December 17, 2014, it was already region-locked this whole time, but the text indicating that it was region-locked wasn't displayed. I've had that happen with one of the gifts I had (spare gift copy spawned from a key activated on 13 September 2015) - it was region-locked to SEA without any explicit text indicating as such.

And it appears that because people complained that gifts did not show whether they were region-locked, Steam only recently made the text showing it was region-locked explicitly appear.

Same thing happend to me, thats messed up man, fuck gaben

It can, many people got troubles with South Park as the ru copies got retro actively region locked even if already redeemed.
I remember even one who got a Trade bane because of it.

By any chance is that one of those games which gives you an extra copy when you activate it? I have one of those (Contraption Maker), I'm guessing that when you activate the ROW gift or key you get the extra key region locked depending on your region, mine didn't say it was locked but when I tried to activate the gift it said that only countries on my region were able to add the game to their library. Now I'm just checking and steam says my gift is region locked, maybe it was just a bug and they fixed it.