To summarize this post. I had to move to Level 2 support and they had a hardware tech come into the shop to try replacing Tray 5 as they suspected a sensor may be faulty. This didn't end up working so level 2 next had the hardware teck re-install the latest software onto the printer, which still did not end up working. Upon follow up with level 2 tech they suggested that perhaps rather than having the software re-installed that the machine should be completely wiped and then reinstall the software.
Despite... instead of fighting further with Tray 5 the hardware tech and I elected to try printing from our tray 6 high capacity feeder. Which ended up working out in the end. I've since printed 2 5-bank tab jobs without issue.