Opinions on Dye Rings?

My NEC 3540a(1.WB) leaves circular rings on the dye side of all discs after burning.I see in the forum that there are many different opinions on if these are a result of a bad burn, burner or just normal because of the NEC changing speeds.
The discs get good quality scores and play fine in multiple players.

Just wondering if anyone had some new info or opinions on this subject ?

Thanks

If the data is delivered continiously to the burner then it should be an speeding change or media related thing.

No buffer underruns , seems to do it on all media i use

If it scans and reads alright, why should it matter?
Maybe it’s because the drive drops the speed a few times during normal write (when it clicks).