When a Sprite that has been created from a Texture Atlas is used in a Widget, it can not be tiled. Instead the whole Texture Atlas is tiled.
Reported in version 4.25.3(CL 13942748). Tested and found in versions 4.25.3, 4.24.3(CL 11590370), and 4.23.1(CL 9631420).
Result: The whole Texture will be used, not only the Sprite image.
Expected: To only tile the Sprite image.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-99990 in the post.