thing:
very strange, and in its eerie impossibility it reminds me of an incident about a year ago. btw, i'm a cognitive psychologist and a good portion of my research involves debunking overly exuberant research claims.
my wife and i were moving from one city to another and had posted an 8.5 x 11" flier outside our local supermarket advertising some items for sale. along the bottom of the flyer were tear-off tabs with our phone number on them.
one day after the flier had been up for a week or so we visited the supermarket. walked past the flier, paused for a few good long seconds and observed that one tab at the bottom had been torn off. both my wife and i observed and commented.
did our business at the market, left, walked again past the flier. all of the tabs were intact. again, both my wife and i saw this, and of course we then carefully examined the flier and verified the intactness, i.e. that nothing had been removed and replaced.
we'd only posted that one flier, so the unlikely possibility of substitution of fliers is definitive excluded...
anyway, what's the explanation? either unfathomable quantum weirdness (ha ha) or consensual hallucination...which seems to be the case in your example as well.
best,
5000