Items in water streams don't fall from big dripleaves, but constantly try

Seems items don't fall from big dripleaves if they are in a water stream, even if item is at the end stopped by a block. It plays a sound like it is trying and the item acts like it is going to drop, but it never happens.  The dripleaf drop sound plays and the item bobs up and down with the sound continuously.

I would expect either no sound and no item motion, or allow it to drop.