Cause:

Inattention to printing.

Solutions:

Ink all four fingers at the same time; print all four fingers at the same time.  Do not print each finger individually.  It is extremely important to print all four fingers simultaneously since this guarantees they are in the proper sequence.  Plain impressions are used to double check the rolled impressions for proper sequence.

Ink and print both thumbs at the same time. This will ensure that they are placed in the proper spaces provided.