This reading is not even noted in UBS4, which leaves the surrounding variants without proper explanation. Merk (9th ed. 1964), based on von Soden, gives in the notes:"His [Tisch.] adoption of readings was not always distinguished by watchfulness to detect trips [eye-skips] of transcribers, as e.g. in John 6:51, where the homoeoteleuton δωσω ... δωσω was obviously the first source of confusion: see also Luke 24:51-52. ..." (Alford, The Greek Text, Vol. 1, p. 77 para.I.)
| εστιν Ta(in) B L 579 D 1071 251 850s lat pl. syv sa+] + ην εγω δωσω rel. f q sypih ar gg bo |
Nestle (24th ed. 1960) gives:
⸂ του εμου א a e r1 sys-s ; T | ⸀ ζησεται P66 B C Hesch.pm; W |
:. Kai comm | ⸉ 5-9 1-4 א m Tert; Th-r1 | ⸆ ην εγω δωσω Hesch. Θ pl f q; h-rs
These are a little more informative apparatus but still terse.
Hodges/Farstad also add a note, while retaining the longer text:
⸂ 1-4, 8-13 P66 (P75vid) B C versus Maj; (8-12, 1-4 א ).
- Which is perhaps more readable.
The traditional text runs:
ειμι ο αρτος ο ζων ο εκ του ουρα-
νου καταβας εαν τις φαγη εκ του-
του του αρτου ζησεται εις τον αιω
να και ο αρτος δε ον εγω δωσω
η σαρξ μου εστιν ην εγω δωσω
υπερ της του κοσμου ζωης...
Although the text as it stands is not a 'pure' homoeoteleuton case, it seems clear there was an error of omission loosely based on similar endings or phrases. Here probably Alford is right, in preferring the Majority text, even though he himself favours the Uncial texts most of the time.