This is related to the discussion we had some month ago about the maximum delay length in [delread~] and [vd~]. Remember: the arguement for [delwrite~] is actually the buffer size and not the maximum delay length (-> bug in the docs).
Apparantly, [delwrite] doesn't check for the minium buffer size and just acts weird if you set it to 0.
BTW: [delwrite~ 1.45125] + [delread~ 0] roughly equals a pair of [send~] and [receive~]