I’m a SysAid Admin and my techs can’t merge tickets in Spaces but I can.  When I check under the group’s user settings, they all have permissions to ’Merge service records’>‘User default merge settings’.  The current workaround is from the service record to go back into the Classic view (Settings>Open Classic Queue) in the active service records window and and merge tickets from this screen.  Before we upgraded to Spaces, the techs could merge tickets without the error that says “Try again later.”