Blender to UE4 Import Issue: Bone/Vertex Weight Problem


I have an issue when importing my player skeletal mesh and animations from Blender. It seems the bone hierarchy shown in the UE4 editor is slightly different to the one in I have created in Blender, as it has some bones collapsed and stuff. This may be the cause for an issue with the hands of my main character. When previewing the skeletal mesh on its own within UE4, everything is perfect. However, when I assign an animation, everything is working aside from the hand meshes which are oddly rotated 90 degrees to the right. This is consistent with every one of my animations for this character, and I have not found a fix. I can assure that it is not a problem with my design of animation or vertex group setup within Blender.

Here are some images showcasing my problem:

Above is my bone structure for my character, without any animations applied.

Above is a screenshot of my character with an idle animation applied; the hand rotation issue is circled in red.

If anyone can help me identify the cause of this problem and point me in a direction to help me solve it, I will be extremely thankful. This is an issue that has bogged me down for almost 20 hours, I just cannot find the solution anywhere.
Thank you.

Nevermind. I solved it by connecting the end of each hand bone in blender directly to the middle finger. This is a problem caused by how Unreal reads and uses bones. So basically, the child bone must always be physically connected to the parent bone (if it has one, and if the child bone in question is a deform bone).