Blu-ray inserts/covers damaged by moisture

[belgavin]

I have 400 or so blu-rays on a shelf in a spare room, the house is fairly old with limited insulation.

I have about 80% of the collection in resealable plastic sleeves. I realise this looks stupid to some collectors but I find it reduces shelf wear to cases, particularly slipcovers which I have a lot of.

I have mostly Criterion and Vinegar Syndrome releases. A few months ago I noticed a few movies had their inserts becoming wrinkled/rippled. These were movies that were not in the plastic sleeves. I figured I should be more diligent in putting them all in sleeves and didn't think much of it.

In the past week, however, I looked at some of the Vinegar Syndrome movies I had, and some inserts have slight to severe rippling even though they're STILL SEALED from the manufacturer AND sealed in a protective sleeve for the slipcover as well. What the hell?! These cases are protected by 2 LAYERS of plastic and the inserts have still been damaged? How is this possible?

Has anyone seen similar for still-sealed discs?

I suppose an argument could be made that the plastic sleeves are the problem by trapping moisture somehow. But the majority of the Vinegar Syndromes are fine, it's just a handful. Also I have 99% of Criterions in sleeves, and the one that has rippled really badly (Safety Last) was one of the only ones not in a sleeve.

Weirdly, I have a 15 or so Masters of Cinemas titles not in plastic sleeves, situated close to all the damaged Vinegar Syndromes, and they're all perfect.

There's no mould or dampness throughout the room except for occasional condensation on the windows. There is a small fishtank (possibly the culprit). I am going to move the shelf to another room and buy a dehumidifier.

I tried to fix the Safety Last Criterion insert by gently ironing it between some fabric. It has improved it, but slight ripples remain.

Has anyone had any luck fixing or reducing the ripples once they're there? Or are they toast?