Stewart - Interesting that it only started after the day light saving change. I have had this issue at a few clients and we used the information below to fix.
SOLUTION ID: 201076548 E1: SCHED: Scheduler jobs run twice when submitted
ISSUE:
In tools release 8.97.1.3 and newer (8.97.2.0 and 8.97.2.1), there's an Interactive Version of P91300 (created by the customer), which exhibits strange behavior: Every job that's scheduled to run within that version gets submitted twice, regardless of the recurrence, creating 2 correct PDF files, with both jobs ending successfully.
For instance, if the scheduled batch job ID is 76153, in Work with Submitted Jobs (WSJ) you'll see 2 job IDs: 76152 and 76153. The cloned job always has an ID of 1 number less, and while the cloned job is being processed, the original one (e.g. 76153) stays in waiting status. As mentioned previously; in the end both jobs end successfully.
SOLUTION:
The SAR that originally caused this issue was # 8789122, which was addressing an issue with XML Publisher.
The POCs that fix Scheduler will be entered into Tools Releases 8.97.2.3 and 8.98.0.1. Customers on affected releases who need resolve this issue and are unable to upgrade their tools release should have an IAR opened to request a POC for their platform/OS version/tools release.
This is fixed in Tools Release 8.97.2.3 and 8.98.x.