Product Configurator constraints for attribute values

On vanilla 8.1.1.3 the attribute values in product configurator are correctly limited by a constraint when you select a value for the first time. However when you select an attribute value for a second time then the drop down list of attribute values incorrectly allows the values to be selected which break the constraint rule. When you select the value that breaks the constraint rule then new product instances are unexpectedly added. How can you prevent attributes values being selected which break constraint “attribute greater than or less than” rules?

 

Product Model

 

Attribute Speed A - Integer Enumerated values 1,2,3 or 4

Attribute Speed B - Integer Enumerated values 1,2,3 or 4