Does UE4's FBX importer mangle UV coordinates outside of the [0,1] range?

I have a static mesh with 2 additional UV channels that I am using to bake data for a shader I am designing. I ran into an issue where the TextureCoordinates of my custom UV channels didn’t seem to be giving me proper values. Here is what one such UV channel looks like in Blender for one particular quad:

As you can see, the UV vertices all lie at either {1,1.44} or {1,0}. Pretty simple, so I went about trying to print this data to the console inside of PIE, [and I found this question where someone posted some C++ code to do just that.][2]

I put this code into my project and tried printing out the UV data of my mesh on this particular channel, and I got this:

269635-untitled2.png

As you can see, none of these V values are correct! U values look okay, since they are all 1, but it’s as if the Vs were clamped to the mod range of [0,1] or something considering some of them are “-0.439209”. It has to be an issue with the UE4 FBX importer, because when I import the FBX file into Blender everything looks good, but what’s really strange to me is that when I open the static mesh in the editor, the UV appears to be displaying correctly when I display them in the viewport:

Does anyone have any information about this? Is there some kind of importer setting I have to use to get it to not mess with my UV values? Or if not, is there some other way of baking vectors into my mesh for use in vertex shader code? Thank you!

I found out what was going on, for anyone who comes across this in the future. For some reason, when unreal engine imports the FBX file it recalculates the UV as {1 - U, 1 - V}… No idea why the hell this is happening but I solved my issue by subtracting the UV values from 1 in the shader graph code. It would be nice if someone could respond and explain to me why unreal engine is doing this and how I can get it to stop doing that if at all possible.

EDIT: Correction, only V is affected. I guess it’s because the texture space axis is flipped on the y axis internally or something?.. Maybe there is nothing anyone can do about this? But even if that’s the case, I feel like something like that should be documented somewhere and none of the unreal documentation I’ve seen about importing UVs discuss this.