I use(d) keepass 2.27 with german translation.
I have marked the option
"Zwischenablage beim Schließen von keepass leeren" which means
"delete clipboard when keepass is closed"
but
I could copy a password to the clipboard, close keepass, install the new version (2.28) and still my password was in the clipboard inspite of having the above mentioned option marked.
I would say this could be a bug.
See the FAQ:
http://keepass.info/help/kb/faq.html#clipovr
Best regards,
Dominik