The enumeration does not appear to contain a consistent set values that can be combined using the OR (|) and AND (&) operators. ...

The enumeration does not appear to contain a consistent set values that can be combined using  the OR (|) and AND (&) operators. Using the Flags attribute on an enumeration suggests that the enumeration values are meant to be combined using the AND and OR operators. Typically, a flags enumeration uses values that are either powers of two, or combine other values that are powers of two.