How to make sure SceneCaptureComponent2D result ain't black

I’m creating a widget in BP, capture it with SceneCapture component and then display it on static mesh. Goal is to have widget displayed on non flat surface.
Problem is that sometimes captured texture is black. I’ve tried disabling ‘capture every frame’ and capturing manually once widget was created but it was black more often.
Currently I left ‘capture every frame’ on, give it 0.2s to render and then turn it of. Works better but sometimes still produces black texture.
Would be great to have a way to be sure that widget was created, rendered and captured instead of hoping that it works within given time (and I’m sure it wont’ work on some machines anyways :P)