In the opening portion of Brahms's "Romanze" (Op. 118, No. 5), the melody is doubled at the octave between the right and left hands, but the corresponding phrase markings are offset from each other.
Does this offset hold interpretive significance, and if so, what?
The below image from the first edition (mm. 1–3) shows one example of offset phrasing, and the Mandyczewski edition follows suit.
Here is a stripped-down reproduction to make clear the "offset" phrasing.
Even though the right hand and left hand voices are playing the same notes (at the octave) at the same time, the first right-hand phrase ends one note after the left hand, and similarly, the next phrase begins one note after the left hand.
The phrase shown above repeats toward the end of the piece (mm. 48–50), and in that case, the phrases align (image below).
Emil von Sauer, in his edition, aligns the phrases both at the beginning at the end of the piece. Measures 1–3 are shown below.
Was Brahms trying to signal something about the phrasing in mm. 1–3, or is it just a proofreading/editing error?
Images of the first and von Sauer editions come from IMSLP.