I've noticed this as well on a few of the of the Stingray's I have played at GC over the last few years...... or buzzy upper register frets from either unlevel frets or a slight kick up in the board at the heel.
However, I had both a fretted and fretless late 90's early 2000's Stingray 5 strings and they were among the nicest built basses I have ever owned.
