I recall there being at least several users with ongoing problems related to
dpms timeout settings getting reset to odd values from time to time.
Related to this,
https://bugs.kde.org/show_bug.cgi?id=295164
There seems to be a proposed fixes in the works,
https://git.reviewboard.kde.org/r/106793/
https://git.reviewboard.kde.org/r/106794/
and was wondering if any of those experiencing this problem would be
interested in helping to test the proposed patches. If so, I can whip up
some builds that include these for feedback.
-- rex