Consider the following examples from different languages:
(en) The bridge has been built a couple years ago.
(de) Das Problem ist größer als vor ein paar Jahren.
(pl) Poznaliśmy się parę lat temu.
(sv) Det tar ett par veckor.
... and I am sure there are other examples too.
Clearly the notion of pair/couple has become to mean more than two (I'd even argue in these sentences it would be a stretch to interpret it as "two or more", to me it sounds clearly as "more than two"). At the same time - in other contexts, in the same languages - the word 'pair' or similar means exactly 2.
How come several languages ended up with such (same!) ambiguity? Moreover affecting involving different stems (~pair, ~couple)