perhaps not a bug with VL, but indeed one with Bjorklund (Collections).
not sharp enough in VL to figure out what is wrong in the Greyed out for each loop in it.
Bjorklund-Bug.v4p (4.7 kB)
weird, Moving the two IO boxes with a 1 and a 0 in the Bjorklund SubPatch and then changing the inputs to the Bjorklund node in the vvvv patch makes it work as expected.
EDIT: still a bug though, it should work on open
EDIT2: if not noticed already, it seems like it is more of a VL problem than with the specific Bjorklund patch