[Omissions not jurisdictional.]

Omission to assess benefits, or to assess for cost of construction, or to make additional assessments, or to make assessment for repairs against, or to award damages to any one or more tracts of land or easements in a drainage district, or to assess benefits, or to assess for cost of construction, or to assess for repairs or to make additional assessments against any corporation which should have been assessed, shall neither affect the jurisdiction of the court to confirm any report nor to render the benefits assessed, or the assessments for cost of construction, or additional assessments or assessments for repairs against other lands, or assessments against any corporation voidable, but the commissioners of said drainage district shall thereafter, as soon as they discover the omission, or receive notice thereof, either agree with the omitted parties upon the proper assessments or damages or make such assessments against the omitted lands and corporations, and award such damages as shall be just, and report the fact, together with such assessments and awards, to the court.