The rule "autocomplete attribute has valid value" (73f2c2) has the assumption "The autocomplete attribute is used on form fields that correspond to Input Purposes for User Interface Components and collect information about the user."

This means that the use of autocomplete="off" is actually not applicable to the rule due to the expectation.

However, I have twice this week had to debug automated testing results (from two different checker engines) that failed autocomplete="off".
I think this is an indication that the rule incorrectly flags a common practice as an accessibility issue.