Digital Cut stops without error

Avid MC 8.5.1
HP z420 | 16GB Ram
Nitris DX I/O
Facilis Terrablock via 8gb Fiber

I am not sure if this is a bug or a setting somewhere but my digital cut stops with out warning or error if I switch to a different program. 

i.e. Digital Cut Tool is outputting to tape and then I click on another program down in the taskbar (in this case visio) and then my digital cut just stops.

In previous version I was able to work on something else while I am cutting to tape. 

Here are the settings I currently see on my digital cut tool 

• Stop on dropped frames
• Digital cut safe mode
• Object mode: real time
• Bit Depth: 8-but
• Add black at tail
• Assemble Edit
• Out to DigiBeta on a Sony DVW-500