Either it's a standard English mistake, or it's a mistake for its standard castellanization.
It is Spanish, the correct term is standard and in standard English. Error by standard or standard . English language word meaning pattern, level, current, common, accepted, normal, classic.
The word "standar" is a deformation caused by "Spanishizing" the English word "Standard", retaining the same meaning in both languages: Common, normal, agreed, ordinary, which contends to generally accepted rules.