Projector + OBS keyed lower third

What's the best way to configure Presenter to show full screen to a projector and lower third with a blue background for OBS.

Before we upgraded to Plus and got the extra display, we had a single output on a lower third template with an image for the background that was 2/3 blue and 1/3 black. That worked fine, but the video was shown in the auditorium, not just on the stream

The way I have it set up now, is the main display is full frame and the lyrics template uses the full image height (albeit with 2 lines). Then I have a second display (dummy plug) that has a solid blue background and the lower third template. This works, but during the transitions, we can see blue fringing that we didn't have before. All the OBS settings are the same, so I'm not sure why it's behaving differently, other than the face we're using the generated background (same #0000FF) versus an image.

Any suggestions?

I would suggest you don't use a background other than black on the OBS lower third display. Then you can key it out in OBS. I have found that any other color than black won't key out completely. Hope that helps.

Thanks for the input.

Before moving to dual outputs, our background image was blue on top with the lower third in black. That keyed just fine without any artifacts.

Of course, if we key on black, we lose the lower-third black background for the text. I may be able to add it back in w/OBS.