In some cases, reduce over a sequence from a primitive vector created with vector-of will return incorrect answers:
Second call should return  just like the first one.
Cause: VecSeq (seq on primitive Vec obtained with vector-of) maintains two flags: i is the total number of elements prior to the current node in this seq. offset is the offset in the current anode. When using internal-reduce on a VecSeq, the starting index for the reduce was using offset and ignoring i.
Solution: Use (+ i offset) as the starting index.