I entirely disregard most small in-specs PIF clusters on proven stable media (here I can't say, I don't have data, yet, about T03 stability : my first burns with them are less than 6 months old...).
The exception is when the defect is visible in the form of a dark spot, which means either the dye was defective to start with, or there was some impurity on the surface during burning (speck of dust...). Laser obstruction (during burn) is not a real issue in most cases (very small unburnt spots) as the error correction system nicely compensates for it (most of the consecutive PIF clusters stay in-specs), but since laser diffraction can also occur (during burn) around the impurity, I'm worried that some burned areas around the spot could be less stable than the rest of the disc, so I reburn if it's something really important. Pure conjecture from my part, no hard evidence as yet, on the contrary the discs in my collection with such clusters caused by laser obstruction/diffraction seem to be just as stable as the rest of my discs, so it's probably a non-issue.
PIF levels there rise to 5-8 as well
Anything out-of-specs I would reburn (unless we're talking PIONEER or NEC scans :bigsmile: ).
Check your blanks, before burning, for small impurities on the surface.. - when talking about very good media, that's the main cause of these permanent PIF clusters.
BTW have you checked that these are permanent, i.e. have you tried to dust the disc and re-scan?