Thanks so much for taking the time to post! This was a new one for me, so I had to ask around a bit!
Basically what’s going on is that there’s a coating applied to the inside of the Form Cure’s clear window. The thickness of this coating is a little variable which is why there can be some differences in how the Cures look.
That being said, the actual performance of the units should all be identical, it just might look a little different from the outside.
Hope that was helpful! I learned something myself!
When my Form Cure is working it looks like the top photo, perhaps even a little darker. It definately works, though. Takes quite a while to warm up. I tend to start the form cure at the same time I start my form wash, that way the cure is at operating temperature around the same time the wash cycle is done.