I've listened to Schumann's 2nd violin sonata a million times and it never clicked for me, I just assumed that his health was failing and he was off of his game, but this week I found a Cello version of the sonata and it is awesome, either I just never found a good violin recording or Schumann's illness was messing with his sense of pitch.

Robert Schumann (Zwickau, Kingdom of Saxony, Confederation of the Rhine, French Empire 1810-1856 Bonn, Rhine Province, Kingdom of Prussia, German Confederation)
(Harro Ruijsenaars, Paul Komen)
Violin Sonata No. 2 in D minor, arranged as Cello Sonata, Op. 121 - 1851, 1st Movement (Ziemlich Langsam, Lebhaft)
https://www.youtube.com/watch?v=CztvJ33yrRE
Violin Sonata No. 2 in D minor, arranged as Cello Sonata, Op. 121 - 1851, 2nd Movement (Sehr Lebhaft)
https://www.youtube.com/watch?v=hf4RTmDBaiw
Violin Sonata No. 2 in D minor, arranged as Cello Sonata, Op. 121 - 1851, 3rd Movement (Leise, Einfach)
https://www.youtube.com/watch?v=SBO_8UqQnU4
Violin Sonata No. 2 in D minor, arranged as Cello Sonata, Op. 121 - 1851, 4th Movement (Bewegt)
https://www.youtube.com/watch?v=ZzQMSJz9rqo