The NodeSet defines (amongst others) the following enumerations:

• "1:OperatingStateEnum" ns=1;i=3014
• "1:CompressorOperatingStateEnum" ns=1;i=3025
• "1:DryerOperatingStateEnum" ns=1;i=3026
  They are all directly derived from "Enumeration" i=29 - no subtyping. Subtyping CompressorOperatingStateEnum and DryerOperatingStateEnum from OperatingStateEnum would also not be allowed according to OPC UA Spec V1.05 Part 3 chapter 8.14. In short: No change of existing value or text allowed, only additional values, no restriction.

The ObjectType "1:OperationalType" has a child "1:OperatingState" with DataType "Enumeration" (is abstract), so all of the above enumerations are good.
The ObjectType "1:CASComponentType" has in its instance declaration "1:OperatingState" ns=1;i=10720 which has DataType "1:OperatingStateEnum", overriding "Enumeration": OK.
BUT: In the derived ObjectType "1:CompressorType", the instance declaration overrides "1:OperatingState" with DataType "1:CompressorOperatingStateEnum", and that is not allowed, because this DataType is not derived from "1:OperatingStateEnum" and such a derivation would also not be allowed. Same situation with the derived ObjectType "1:DryerType".