Yes - we have three environments - Test, Staging and Production - and all produce the same result.
I think but I am not sure that something in the Moodle code is kicking this added .jpg out in Adaptable theme after a restart. Almost like it resets the background to the default color with no regard for an added file to replace.
Again, it’s not like I can’t add it back and it doesn’t work. It does. But having to “delete” the .jpg and then re-add it to bring the background up is annoying - across the three servers no less.