The videos + screenshots in the zip file show the issue on the modified gun sight.
The licensee has provided a suggested fix here -[Link Removed]
Download the licensee repro here - [Link Removed]
Paste the code over the shootergame demo code (just replace the files one to one)
Launch from editor or Buildcookrun shootergame for Win64
Open the sanctuary map, then call the command debugCreatePlayer 1
Observe that the translucency of the sight has additional (green) colouring in view 1 suddenly, which is also seen in the reflections.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-125073 in the post.