Has anyone had little spots of oxidation/corrosion on the liners of SAK's stored

[MacGyver]

Just like the title said:
Has anyone ever had little spots of oxidation/corrosion on the liners of SAK's stored in their boxes?

This weekend i went through all my stored SAK's, mostly backups for my favorite models, or some i don't EDC much, i keep them stored in their boxes with two rows, one on top and other on bottom, and for some reason about 4 of them displayed little spots of oxidation/corrosion on the "spine" of the liners.
It was nothing major, but clearly 2 or 3 spots of corrosion.
After investigating, the only ones that displayed that where the ones where i had the Vic leaflet on the bottom of the box, with the SAK on top and the liners "spine" resting on it.
The ones where there leaflet was folded on the side or around the SAK where all normal. It may have just been coincidence or  some accumulated moisture (very unlikely).

I'm puzzled by this. This was a Climber and a Huntsman from around 2010, a Super Tinker from 2017 or so and a Silvertech Huntsman from around 2019, all NIB.
I wonder if the ink from the printed leaflets might have something to do with that... 

Weird...   

[NutSAK]

I haven't.  I would suspect humidity, as the paper would absorb that where a plastic tray would not, and the cardboard to a lesser extent than the paper.  Do you monitor humidity in the area that you store them?  I think the max humidity any of mine have been in is around 50%.

On second thought, maybe not...  It could also just as easily be a chemical reaction to an ink or solvent used in printing.  I always store the leaflets either under the tray with those older boxes that have the tray, or against one of the scales in cases where there is no tray.

[MacGyver]

I haven't.  I would suspect humidity, as the paper would absorb that where a plastic tray would not, and the cardboard to a lesser extent than the paper.  Do you monitor humidity in the area that you store them?  I think the max humidity any of mine have been in is around 50%.

On second thought, maybe not...  It could also just as easily be a chemical reaction to an ink or solvent used in printing.  I always store the leaflets either under the tray with those older boxes that have the tray, or against one of the scales in cases where there is no tray.

I have all of them in a drawer on my bedside table in my bedroom. It's reasonably dry, i think .  I can however line the bottom of the drawer with some plastic sheet or similar to avoid absorb any moisture from the wood... But i don't think that's really the issue..., as it only happened to those specific ones.
It's probably something in the ink on those leaflets that react with the aluminum of the liners.