Yes, sp_update_job solved the problem because it flushes the SQL Server Agent cache.

exec @Severity=[msdb].[dbo].[sp_update_job] @job_name='JDN_BRD_Play 2', @enabled=@EnableIRMSjobs

It also solved the problem that was the initial symptom of the problem in that when jobs were re-enabled, it did not reset the Schedule with the next time it should run during the day, but waited until the next start of the schedule period to run. But the flush of the cache also reset the schedule correctly.

Thanks Lynn for all your help (both on this issue and all the other responses on other questions).

Bruce