Big problem with max and maxlength, validation of max and maxlength is not consistency

I try to test something in modeler so i set some input in form field modeler with Type:String , minlength = 3, maxlength = 5 but when i try this in engine i got a problem , for the minlength its ok i can able to type in 2 length but when i try to type something that got length 5 the engine Cannot submit task form 8bea4460-de61-11e8-b485-9cda3e8af651: Invalid value submitted for form field ‘ids’: validation of maxlength(5) failed i dont know why this happen it not greater than maxvalue but i cant able to use maxlength
so sry for my english if u not understand just let the image explain to you

As metnioend in the above forum link, one option we use to work around this is: Form Server Validations: Generic Form Validator using Javascript