Noticing with f23 and konsole5-15.08.3-1.fc23.x86_64 that when I scroll past the bottom of the terminal window some lines disappear. So instead of everything scrolling up some lines just get erased.
Ahhh... looks like it's known... Just FYI then.
https://bugs.kde.org/show_bug.cgi?id=356723
Cheers, Brad