Aderant Expert connector fails with "The transaction associated with the current connection has completed but has not been disposed" after a previous SQL timeout failure

After a SQL timeout it appears the SQL connection to Aderant Expert remains with a SQL transaction that has not been disposed.  The error is:

20191203,23:22:24,UNIFYBroker,Connector,Warning,"Update entities to connector failed.
Update entities [Count:2071] to connector Global Aderant Expert Connector failed with reason The transaction associated with the current connection has completed but has not been disposed. The transaction must be disposed before the connection can be used to execute SQL statements.. Duration: 00:01:01.0504286

The previous timeout error responsible for the undisposed transaction is:

20191203,23:16:16,UNIFYBroker,Connector,Warning,"Update entities to connector failed.
System.Data.SqlClient.SqlException (0x80131904): Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding. ---> System.ComponentModel.Win32Exception (0x80004005): The wait operation timed out
Update entities [Count:2071] to connector Global Aderant Expert Connector failed with reason Execution Timeout Expired. The timeout period elapsed prior to completion of the operation or the server is not responding.. Duration: 00:01:16.0479697

The workaround is to restart the UNIFYBroker service, to stop it reusing the bad SQL connection.

See also https://voice.unifysolutions.net/communities/6/topics/3995-aderant-expert-agent-ui-doesnt-save-changes-to-the-operation-timeout-parameter for more information about SQL operation timeouts on a Global Aderant Expert connector.