I hope someone can help me. I am an artist and create resin paintings with inlaid (glued) pressed flower parts.

Now the problem has arisen that some pictures that I had already cast in resin about 9 months ago suddenly became milky and cloudy. This only affected some of the images, other images remained clear.

I then poured resin over them again and the cloudiness was gone again (so it probably only affects the surface), but it makes me very insecure, because I also sell my pictures and of course I don’t want the pictures to suddenly become cloudy at the buyer.

What can be the reason for this? The pictures were certainly hardened after such a long time. Do someone have any other idea? Should I use a clear coat to protect the surface?