I have noted the following errors in my copy of the Norton facsimile, 2nd edition (some or all of them may have been corrected in subsequent reprints). They have been corrected on this website.

PAGEPLAYERROR
H2vThe Comedy of ErrorsLine 1467 has been numbered 1470 by mistake. Both lines end with "heere in the Citie" so that may have induced the error.
P1vThe Merchant of VeniceBlayney's introduction gives the compositor attribution as C/B/C. This should be C/D/C, as confirmed by the paper by O'Connor that he cites.
T4vThe Taming of the ShrewBlayney's introduction gives the compositor attribution as C. This should be B, which was given by Hinman and has not been revised since.
χ2rTroilus and CressidaThe line numbered 190 is actually line 191.
cc4rTitus AndronicusBlayney's introduction gives the compositor attribution as E. This should be B, which was given by Hinman and has not been revised since.
Gg3rTimon of AthensHinman had assigned the page to Compositor B. Howard-Hill reassigned it to Compositor E. Blayney's introduction credits Howard-Hill with the attribution but wrongly gives it as B.
ll3rJulius CaesarHinman had assigned the whole page to Compositor B. Blayney gives the attribution B/E for this page, citing the 1976 paper in which Howard-Hill assigned part of column b to Compositor E. But Howard-Hill had retracted the attribution in 'New Light on Compositor E of the Shakespeare First Folio', The Library, 6th series, 2 (1980), 175.
rr6rKing LearHinman had assigned this page to Compositor E. Blayney's introduction omits to note that this page was reassigned to Compositor B by Howard-Hill.

In addition to the above, Blayney's introduction credits attributions for pages E6v, K1r, K1v, K2r and M1r-M3v to Howard-Hill. In fact, Hinman had made all these attributions in his detailed discussions in volume II but doubted them in his summary at the end of the book.