Weirdness inside double glazing

[Thingsthatgo]

These white marks have appeared inside a double glazed window. They are not big, about an inch or so. Does anyone know what they might be? The rest of the window is a little wavy looking, like the laminate is coming away inside maybe?
The weird thing is it comes and goes... this morning it had disappeared completely. Maybe heat related?
I've only noticed it twice, but the marks are exactly the same, and in the same place when they came back.

Anyone?

Is it laminated glass?

@Surplus2requirements I think so... isn't all double glazing laminated?

@Thingsthatgo no it could be toughened but thinking about it I don't think that's the issue.

I suspect your problem is many sealed units have a film on the inner pane to help reflect heat back into the room (but not the other way around iycwim), and it's no longer bonded properly to the glass

@Surplus2requirements ah! Ok. That makes sense. It's weird that it comes and goes. Maybe the weather conditions affect it. I guess I'll need to replace it. Thank you for your help.