Originally posted by Dipper Any opinions to what this could be due to?
Something inside your camera related to the shutter sequence is not proper.
Originally posted by Dipper Could the shutter be about to break completely ?
Perhaps, though the source of the problem may be something other than the shutter (mirror or aperture actuator).
Originally posted by Dipper Is it "normal" that before failing it gives "warnings" like this, or is it more likley to be something else going on?
Hearing a funny noise is a time-honored indication of ongoing mechanical problems. What more can we say?
The K-3 shutter is rated for 200,000 actuations and yours is only halfway there. That does not mean it is not failing, only that it is not supposed to be doing so yet. The best answer might be provided by a repair facility. With any luck, a fix might be inexpensive and if not, at least you have a firm indication that finding a replacement might be a good idea.
Steve