🚀 go-pugleaf

I have noticed a strange bug in Mac OS X 10.1.6, on an iBook.

Everything will be fine for some time.  Then after some hours/days of
having the machine running, often (but not always) after one or more
sleep/wakeups, single- or double-clicking on the main desktop Hard Drive
icon will cause it to change to a darker-grey version (as usual) but
with one, two or three thick black horizonal bands across the icon. 
Often the icon does back to normal when it is deselected (so that it
goes back to the lighter shade of grey), but after this behaviour has
been going on for some time, the lighter grey icon also gets corrupted
in the same way.  Later, the Hard Drive icon at the top of the Computer
folder goes the same way.  Also, the number or density of black
horizontal bands can get worse and worse.

Restarting puts things back to normal... for a while!

Has anyone seen similar behaviour?  Any educated guesses about the
cause?  And most importantly: Is there a cure? (please don't say upgrade
to Jaguar or Panther - I'm intending to do that sometime soon anyway)

I do not autoload OS9, and never use the iBook in Classic mode.

Cheers,
Vaughan