Updates applied to sys_dictionary_override fail to coalesce on 'name' index and instead match on sys_id despite the presence of a unique keyDescriptionWhen attempting to use an update set to modify or create sys_dictionary_override records, any override that already exists for an element will not coalesce despite the existence of a unique index called 'name' for the 'name' and 'element' columns on the sys_dictionary_override table. This is because sys_dictionary_override uses the default coalesce strategy of sys_id vs. sys_dictionary which coalesces on the name and column. The system interprets the new sys_dictionary_override record as an insert if the sys_id does not match but the unique constraint on table and column at the db level prevents it from being loaded as a net new record.Steps to Reproduce Have two OOB instances of the same version ready, New York P1 or higher.On Instance 1:1- Create a new update set in the Global Scope and make it the current update set.2- Go to the Dictionary, and find the "test_plan" column record for the 'change_request' table.3- Switch to Advanced View, and go to the Dictionary Overrides related list, and select New.4- Change the Default Value to anything, such as "new default value" and save the override.5- Go to the update set record and mark it as complete.On Instance 2:6- Make a dictionary override on the same dictionary record from Instance 1 to the version on Instance 2. Change the Default Value to be "changed default value".7- Configure this instance to pull update sets remotely from Instance 1. Pull the remote update set modifying the dictionary record.8- Preview the commit of the remote update set. Notice that no errors are thrown.9- Commit the update set. You will be notified of an error. Open the logs to find a "FAILED TRYING TO EXECUTE ON CONNECTION… Duplicate Entry 'change_request_imac-test_plan' for key 'name'".WorkaroundAfter carefully considering the severity and frequency of the issue, and the cost and risk of attempting a fix, it has been decided to not address this issue in any current or near future releases. We do not make this decision lightly, and we apologise for any inconvenience. There are two possible workarounds to mitigate the issue: Prior to changing/creating the override, export the target sys_dictionary_override record for the same table/column and import into the source system where the change is being made. Once the override has the same sys_id, it should coalesce properly to perform an update rather than insert.Remove the dictionary override from the target system before applying the update set to avoid the unique constraint during insert. (This may change the behavior of the target system until the update is applied and likely should be performed during the change window introducing the update set).Related Problem: PRB1399581