Skinning on Skeletal Mesh is broken

I have created a character in Blender 2.75 and used Rigify to rig it (The character was created in Blender 2.74 tho, I had to reinstall due to a unforgivable glitch with export scale).
I have imported the skeletal mesh several times in Unreal encountering various problems, but I never got this one.

The problem is: When I import in UE4, the kness and pelvis are squashed inward.

As I said I have exported many times and I haven’t changed the export/import settings, but now I have this problem.
I have tried to import the FBX back in Blender and it worked fine, but it gets broken in UE4.
Only the knees and pelvis are squashed, the rest is okay.

Hopefully someone knows what this is. Thanks for your time,

  1. How many bones are affecting the vertices in those areas?

  2. If you swap to the “skeleton view” in both Blender and the Unreal Editor, is there any difference between the bone positions/rotations - or do they match up perfectly?

  1. Knees had both two bones, Pelvis had 4 bones.
  2. Both views were identical.

I have found the problem, I’ll explain in a new Answer
Thanks for your help!

Glad you got it working! Looking forward to see your solution.

I have found the problem! My character has a jumping animation which bend the knees and pelvis.

That animation was on top of the Action List in Blender and Unreal considered the frame 0 of this anim as Reference pose. (I didn’t think that would deform the model permanently)
So the solution is to make sure your T-pose is on frame 0 on the first animation.

or don’t Use T0As Ref Pose when importing in Unreal (I learned to use it on a tutorial, but it’s not really necessary)