Widget-components in 4.22 get motion-blurred while motionless. Is this a setting or a bug?

See screenshots - I’ve migrated two unrelated projects from 4.21 to 4.22, and for both in 4.22 all widget components get incorrectly motion-blurred, making the UI unreadable while the player is moving. Does anyone know how to fix this?

Normally if motion-blur is enabled, a mesh or widget should blur if it’s moving through your field of view, but if it is attached to camera (or otherwise motionless relative to your field of view), it should not blur much because it’s not visibly moving. This is how 4.21 did it. In 4.22, meshes still motion-blur correctly like this, but when a widget is motionless onscreen yet the background is shifting (or if you are walking so that your camera and its child-widget is moving through space) the widget blurs out even though it’s not visibly moving, (presumably because it is moving relative to things around it, and/or is moving through world-space even though it’s not moving relative to the camera view)

I’ve tried messing with a ton of settings (and searching for possible new settings in likely places) but I haven’t made any progress.

(This seems like a bug, but it also seems problematic enough that I would have expected others to hit it and to be able to find references to it. So I’m wondering if instead I might be using some unique combination of settings that are producing the effect. Has anyone come across this?)

Does anyone have a widget-component NOT exhibiting this behavior in 4.22? (ie using motion-blur, a widget component in world-space attached to player camera so that it’s stationary onscreen, player moving through the world so the view is changing except the widget, and the widget draws correctly the same as it did in 4.21)

  • The widget-components are in world space (and need to be)
  • Static meshes blur correctly - when motionless on screen but moving through space, they don’t blur, yet a widget attached to them does blur.
  • The issue persists with a wide range of widget component settings, project settings, etc.
  • Are there any specific details I should provide that might help?

This is an old issue and didn’t find anyone else posting the following workaround so for anyone else coming across this issue it seems to be caused by the material being User Interface type. You can fix it by creating a new material with type Surface and a Texture Parameter with the name SlateUI (this is what the Widget Component uses to display the content). You can then do whatever surface shading you want with it, for a simple test just connecting it to base color and then change the widget component to use the new material, blurriness caused by both Motion Blur and Temporal AA should now be fixed.

PS. I just figured this out so there might still be some weirdness, one thing I did notice is that if cast shadows is left on for the component they’re still affected by the blur but at least for my purposes the widgets won’t be casting shadows so that isn’t an issue.