Today I was listening to the Greek Audio by Schwandt on 1 Corinthians 15. The last several words of 1 Corinthians 15:2 are missing. The missing words are: ἐκτὸς εἰ μὴ εἰκῇ ἐπιστεύσατε.
The Byzantine Textform 2005 audio has the words in the recording.
