Member states will implement this into national law. So in the case they will need to implement a maximum of one year or more (but not less). The final law as applied by a judge will just read "punishable by a maximum of [i.e.] fourteen months".

"Maximum term" is a specific legal concept, "at least one year" is the numerical constraint.

Or, put another way:

  if(maxTerm >= 1) {
    // law implementation OK!
  }