Originally Posted by
Jaimito Cartero
In the 55 countries I've been to, I can't recall ever seeing them stamp a page and then put a sticker on. I'd think it more likely something that was built into the sticker, that left the residue.
Other than those countries which issue visas at the border crossing, I've never seen visa being issued.
Often, one needs to wait few hours, days, weeks between applying for it and collecting the passport. [based on UK, lot of Schengen countries, South Africa, US, Canada....etc]
So, they could easily stamp the page before putting a sticker on it.