Hi there is nothing wrong with it, mask is doing its job. If you want to mask everything with material then you have to provide exact shape to the material. Which would be hard case for your.
If your mask is not matching this is the result, however in your case you don’t even have to use this anymore since you are doing it in a single UMG. (that was not the case in the beginning of this forum thread)
You can wrap your object with a size box and use bounds clipping.
That way your widget on back still will be clipped and you don’t need a material masking that way.
