Deformed Apex Clothing in UE4.9 (Blender)

I made the flag I’ve seen in this video Blender UE4 Cloth - YouTube.
The armature works properly in blender and everything looks fine in Apex too. I didn’t make any collision volumes on the flag mesh. But there’s a thing that the “generate tangent” button in Apex is disabled. Anyway everything is correctly imported in UE but assigning the .apx to the flag causes it’s deformation. There is also a message: “This APEX clothing asset doesn’t have Tangents data! It could be old format. This can introduce rendering artifact.”. However in the video is the cloth simulation correct after this message. I checked the “used with clothing”, “used with skeletal mesh” and “two sided” options in the material settings. The flag is only deformed if the simulation is running. I have no clue what the problem could be and why is the “generate tangent” button disabled. I’m adding some screenshots and hope for your help.

I found out that lowering the scale ~100 times in blender will help with this problem. After placing the flag with the .apx file in the UE world everything works correct, even if you increase the scale 100 times in Unreal Engine. But this works fine only with low poly objects. I tried this with makehuman characters and lowering the scale will cause untextured spots on the high poly areas like the face or hair.
I would be grateful if you could help me solve this issue.
By the way the problem with the tangents button in Apex was solved by creating a UV map in blender.

Thank you so much. That fixed the problem for me!