Textures broken on animated mesh, but only in unreal.

​​​​​Textures look fine in unreal editor, and before animations run - but when animated the uv seems to distort around certain polys. The effect is static (not like its deforming around bones or the animation.

animation with textures looks fine in blender, any ideas?

Looks to me like something to do with lightmaps or overlapping UVs, but its obviously not a static mesh?

thanks guys.