Deadlocks With Read Repeatable Isolation Level
If a custom business object uses an isolation level of read repeatable to access a SQL Server, and the business object is called simultaneously by two clients that send a query and update in the same transaction, a deadlock is possible. Remote Data Service is designed to allow one of the processes to time out to release the deadlock, but the update will fail for that client.
Use the Cursor Service Command Time Out dynamic property to modify the length of the timeout.