AD Connector ObjectSid field not working with Postgresql

When running an import on AD Groups, the objectSid field is defined as a string on the connector schema. SQL can import this field fine (although shows as jargon on the UI). Postgres fails to import with the following error:

Connector Processing page 1 for connector On-Prem Groups failed with reason 22P05: unsupported Unicode escape sequence. Duration: 00:00:08.3359933.
Error details:
Npgsql.PostgresException (0x80004005): 22P05: unsupported Unicode escape sequence
at Npgsql.NpgsqlConnector.<>c__DisplayClass161_0.<<readmessage>g__ReadMessageLong|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Npgsql.NpgsqlConnector.<>c__DisplayClass161_0.<<readmessage>g__ReadMessageLong|0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at Npgsql.NpgsqlDataReader.<nextresult>d__46.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Npgsql.NpgsqlDataReader.NextResult()
at Npgsql.NpgsqlCommand.<executedbdatareader>d__100.MoveNext()</executedbdatareader></nextresult></readmessage></readmessage>

Changing the field type to 'binary' and attempting an import yields a different error at an earlier stage:

nify.Product.IdentityBroker.EntitySchemaValidationException: Invalid binary - the value was a string, but was not able to be converted as a base64 encoded string from: ??? ? ---> System.FormatException: The input is not a valid Base-64 string as it contains a non-base 64 character, more than two padding characters, or an illegal character among the padding characters.
at System.Convert.FromBase64_Decode(Char* startInputPtr, Int32 inputLength, Byte* startDestPtr, Int32 destLength)
at System.Convert.FromBase64CharPtr(Char* inputPtr, Int32 inputLength)
at System.Convert.FromBase64String(String s)
at Unify.Product.IdentityBroker.EntityBinaryTypeSchemaValidator.CreateValue(Object dataValue)