Download the licensee repro from here and open in editor: [Link Removed]
Go to PIE, set r.RectLightAtlas.Debug 1, press numbers 1 and 2 to switch between levels. 1->2 streams in the rect lights, 2->1 streams them out. This works correctly in Editor.
Package or Launch the game client/version from the editor, follow the same steps, r.RectLightAtlas.Debug 1 and switch between 1+2. The texture count constantly increases, likely the rect light texture doesn't stream out. (Image attached of the issue).
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-187663 in the post.