Also, the AES format includes both a electrical format (110 ohm impedence and I think a 5v signal for digital 1) and a word/information format. Things like the V3 jumpers and format converters will convert to the SPDIF electrical standard (75ohm, 0.5v), but will not convert the (24-bit? or 32 bit?) word format. Embedded in each "word" of information are the 16 bits of sound info, plus other signal info including SCMS info bits.
It might be that you were using a 24-bit music format, I don't know how that affects a D7/D8 deck. But if the DEVA is sending a professional signal that doesn't even include the bits for SCMS, the P1 will read that (since it is a pro deck), but it will just pass along the data without adding the SCMS bits into the data words. A D7/D8 getting this signal with no info on SCMS whatsoever will read that as unacceptable from a SCMS standpoint and will give the "copy prohibit" message. Bottom line, even though the P1 might have acted to change the electrical signal to that conforming with SPDIF, it won't alter the pro data format information.