What is going on here in Matthew 20:15? The Majority text reads:

Ἢ οὐκ ἔξεστίν μοι ποιῆσαι ὃ θέλω ἐν τοῖς ἐμοῖς; Εἰ ὁ ὀφθαλμός σου πονηρός ἐστιν, ὅτι ἐγὼ ἀγαθός εἰμι;

Here are the two significant variants in the verse, showing only witnesses 8th century and earlier:

η ουκ…ει ο οφθαλμος lat Chrysostom TR RP ‖ η ουκ…η ο οφθαλμος ℵ C E N W Σ Φ 085 syr-p,h cop-sa TH [NA28] ‖ ουκ…η ο οφθαλμος B* D L Z SBL ‖ ουκ…ει ο οφθαλμος B² ‖ lac A P 0233 0281. 

All the witnesses above except B D L Z SBL begin the sentence with the Greek word Ἢ, “or.” Then the TR and Majority text for the second variant read ει, a marker for a direct question. What I am pointing out is that none of the English translations based on the Majority reading translate the word Ἢ as “or.”

BUT, neither do the English translations based on the second reading, which has the Greek word η for both variants, neither do they appear to render their text as it is found.

Practically none of the English translations translate the first η as “or.” 

The translations supposedly based on the TR / Majority text, at first seem to read as the Vaticanus corrector. (ουκ…ει ο οφθαλμος B²). The English translations from the Syriac, the Etheridge and Murdock translations, also seem to read as B².

The EMTV, “English Majority Text Version, reads as the SBL text.

We have seen that none of the English translations translate the first η as “or.”  But they are probably not following the reading of B* D L Z Θ SBL. The BDF grammar in Sec. 440 (3) says a simple interrogative ἦ does not exist in the NT.  In Sec. 440 (1) DeBrunner gives four examples in the NT of “simple interrogative ἤ,” Matt. 20:15, 26:53; 1 Cor. 9:8; 2 Cor. 11:7.  This must be how the first η is being interpreted.