Issue with exposure while using opacity

Hi all,

I am trying to do a timelapse of the blood moon, using 36 frames. The way I am doing it is using 36 photos, 1 second each, and having the the following photo on top of the previeous one on the timeline by the 0.5s mark, and have it's opacity going from 0% to 100% with keyframes.

The issue is that the image is pulsating and I don't know why or how to solve it.

https://youtube.com/shorts/1nnJ7fygq1U

Thank you for your help.