Nevermind guys, aparently, there is NO easy way of adressing this problem due to the nature of Maya's UVs. Aparently games companies adress this by getting one of their engineers to create some extra code with maya's model exporter. Just thought I'd save anyone who runs into the same problem the bother of hunting for an answer.

In my previous post, I mentioned reversing the normal direction on the erroneous half of the model. While this works, it produced a distinct seam down the middle (maybe it was just the model, give it a try, might work fine for you). If however, like me, you get this seam, the most feasible solution with regards to saving texture space seems to be, to have overlapping UVs ONLY on geometry that come in pairs but don't actually connect or touch, i.e. gloves, boots, shouder pads, etc. On something like a cuirass/body armour/torso, it's probably easier to just map the whole thing as one uv set.

If you wanna know more, check out the following link. It gives a better explanation of the nature of the problem. Scroll down to "Flipped UVs Issue". It's a great Normal Mapping tutorial by the way.

https://www.bencloward.com/tutorials_normal_maps10.shtml