Movie Render Queue 5.1 - ProRes and Avid DNx exports no longer rendering burn-ins

Since upgrading to 5.1, I have noticed that burn-ins don’t appear to render at all using ProRes and Avid DNx export options.

I did a comparison, and noticed that burn-ins still render if I render a JPG or PNG image sequence.

In all cases, the level sequence itself renders fine, but there is just no burn-in visible at all using ProRes or Avid DNx.

I have tested this using both our team’s projects, and also using a brand new blank project using UE’s Default burn-in. Example setting below.

This appears to be a bug?