Dented Boxset-Sleeves

[Damage Inc.]

Hi, I have another probably weird question here:

You know those more sturdy cardboard sleeves for some box-sets right?
For release such as 'The Godfather', well, the UK-version or in this case 'The Ultimate Matrix Collection'.

Well, a lot of times the front and sometimes also the back sides are caved in.
Like they run hollow towards the inside.
Is this normal or is this "damage" because of pressure from something else?
I was thinking it might also be because of the sealant being tight around it, but I have my doubts...
This isn't always the case though, sometimes another copy of the same release might look better.
But I'm not sure which occurs most...

Anyway, will this pull straight again eventually or can I do this myself or is it just... as it is now?...