I only meant to point out that the interval actually sounding is an augmented 5th relative to the E--to be precise, in order to call the interval an augmented 5th,I should have called the note a B#, but didn't to avoid making things more confusing--

Also--as to what notes are enharmonic and not, violinists play natural scales, in the unlikely event that they were playing in C# major, the B# would have a slightly different pitch than, say, a C in C major.