UMG Border image scale or tile takes a long time when displayed

Hello, I have a texture image, 512x512, and am using it in a border widget. Drawing as an image, tiled both ways, the image is a simple checker of two shades of grey. When it draws on screen, about 1200x1200 pixels, it first draws as a solid single shade of grey and about 3 seconds later the pattern appears, I have tried with other textures and a similar thing is happening.

Any idea why? All the other more complex widgets that draw on top of it (buttons etc) appear instantly and are properly drawn.

I have made a small project to demonstrate. When playing in editor it works instantly, when running as a standalone game or if it has been packaged it takes several seconds to show the texture…sEOiQ-LyJ/view