Digital BW, The Print

Quite a shocker..  I had a bunch of inkjet prints sitting in a pile on my desk, most printed 
on EEM but I had made one print on photorag 308.  All these are prints I had made in the 
last couple of days.
This morning I glanced over at the pile of prints and... there was one that had turned a 
bright garish yellow, almost chartreuse!  It was such a bright yellow that I just couldn't 
believe my eyes..  all the others were fine, and it was the HPR print that had turned this 
outrageous color!  The yellow is only on the coated side of the paper, the other side is 
unaffected.
It happens that the HPR print was sitting on top of a newspaper, so I did a little 
experiment.. I took another sheet of HPR and set it on top of another piece of newsprint, 
and after just a few hours it's starting to change color too!  Another bit of oddness is that 
the original print is losing it's yellowness now that it's no longer near the newspaper.
Just to be clear about this, the HPR print was lying image side up on top of the newspaper.  
The coated side wasn't in contact with the newsprint.. so whatever reaction took place was 
not through direct contact with the coated side.
Just thought I'd post this in case anyone else had photorag that suddenly turned bright 
yellow on them:  it's because the paper is near newsprint, I just can't explain why!