Hello Gene,
Seems to be a well know documented bug:
https://bugs.kde.org/show_bug.cgi?id=182104
Workaround from comment 11:
Add the following line:
EffectsEnabled=false
to the end of the file:
~/.kde/share/config/kslideshow.kssrc
I am also affected by this bug. Thanks a lot for this workaround.
Cheers,
Volker