It is normal behaviour...
That's weird because I don't ever recall this behavior with any application or distro prior to Mint 16 or 17.
What's even weirder is that today LO Writer now clears the clipboard on exit as well. It did not do this yesterday.
go figure. However, LO is still the only application that does this.
Re: clipit: I don't want my clipboard contents cleared to begin with and don't need a clipboard manager yet, though I'll keep that in mind next time I do an insane amount of copy-pasting.
A simple checkbox option in LO to enable or disable clearing clipboard would be nice.
All the best