I know this thread is old but i'm facing a similar issue where I am not able to filter on Enums using the Dynamics Finance and Operations Connector (using CDS is not an option). In my App I have the following filter
In this case Invoice is a custom Enum field. I get the following: An error has occurred. A binary operator with incompatible types was detected. Found operand types 'Microsoft.Dynamics.DataEntities.EnumField' and 'Edm.String' for operator kind 'NotEqual'.
I have seen a solution posted to convert the enumfield into a string to compare however this will make the query non-delegatable and therefore is not an acceptable solution.
I know the correct Odata Syntax for this however I can't seem to cast the "Null" string as the enum type through the filter function.
Is there a way to filter on Enums using the finance and operations connector and still maintain delegation?