I am trying to use armor but am having a problem when applying it as a skin for my character. What am I doing wrong? I have found that the culprit is the exporting from blender to UE5.
Is it using the same skeleton?
Is the skeleton using the same reference pose?
The one on the left is a skeletal mesh just sitting there. The one on the right is the same skeletal mesh but on the character, which I made invisible to show the distortion. I think my issue is my blender and unreal pipeline. I am going to follow this, Exporting the Mannequin Skeleton from Unreal Engine 4 to Blender and Re-importing | Unreal Engine Community Wiki from now on. 
My question is about how the original character skeleton is rigged, and how your mesh is rigged, not about what you’re doing in the game.
The skeleton needs to be the same for your armor as it is for the base character (“the same” meaning the same hierarchy, bone lengths, bone names, and rotations,) and the reference pose need to be the same, when you export/import.
They are both ue4 mannequin skeletons. The mesh is rigged to the skeleton of other armor that works fine on the player’s skeleton. When I imported the fbx from blender there were no changes in the skeleton. And that guide’s directions aren’t working, I am using the mannequin_SK and can see the distortion better.
I hope that I better answered your question. Because I appreciate your help.
In my experience, these problems always come from some mismatch in the skeleton rig or the skeleton reference pose. If you’re absolutely certain your mesh and your armor use exactly equivalent skeletons in Blender, then I don’t know what else could cause it, though 
(unless there’s some version-specific bug with whatever versions of things you have installed, which is always a pain to debug, but I’m not aware of any such problem in particular.)