This kind of beaming often indicates that that very passage in Violin II has a displaced accent when compared to the other instruments: while they follow the time signature changes, from 2/4 to 3/4 and back to 3/4, the second violin keeps a metric accent likewise to 3/4 throughout all the selected excerpt. The beaming serves to guide the player through the correct phrasing and articulation (the arco down/up marks are a further hint of the effect desired by the composer), instead of introducing a more complex layer of polyrhythm (once the metric change is temporary, it is more practical to indicate the division in place without changing the overall feeling of the excerpt).
Violin II could be notated as follows:
without loss of meaning, but it would require polyrhythmic notation, which could be more frightening and awkward than it actually is. By simply changing the beaming, you get the same effect without disrupting the overall character.