ID 419063 - Monitor output fails/turns black when swapping between the Nuke Viewer and the Timeline Viewer or between formats

Problem summary
Monitor output fails/turns black when swapping between the Nuke Viewer and the Timeline Viewer or between formats

This happens when using Blackmagic Decklink drivers 11.0 or newer

Customer reported version
nuke.12.0v3

Customer reported platform

Steps to reproduce

1) Open Nuke Studio with Decklink drivers 11.0 or newer

2) Import some footage and add it to the timeline

3) In Window>Monitor out, enable the Blackmagic monitor out device

4) Switch to the Node Graph panel, and create and view a Checkerboard

5) Switch between the Timeline and Node Graph multiple times, eventual it will error saying: 

Internal error initializing "Decklink 4K Extreme" device: 3

and in terminal it can say:

Failed to acquire device 'DeckLink 4K Extreme'

Expected behaviour
For monitor out to keep working

Actual behaviour
The driver crashes which prevents it from being used 

Workaround
Use Blackmagic Driver 10.11.4 or restart Nuke Sudio

Reproduced by support
This bug has been reproduced in:

Nuke 12.0v3 - Driver 11.4 - Windows 10

Nuke 11.3v6 - Driver 11.4 - Windows 10

Nuke 12.0v3 - Driver 11.2 - Windows 10

Nuke 11.3v6 - Driver 11.2 - Windows 10

Nuke 12.0v3 - Driver 11.1 - Windows 10

Nuke 11.3v6 - Driver 11.1 - Windows 10

Nuke 12.0v3 - Driver 11.0 - Windows 10

Nuke 11.3v6 - Driver 11.0 - Windows 10

Unable to reproduce bug in:

Nuke 12.0v3 - Driver 10.11.4 - Windows 10

Nuke 11.3v6 - Driver 10.11.4 - Windows 10

QA also reproduced this on CentOS 7

Earliest version tested
Nuke 11.3v6 - Driver 10.11.4 - This issue appears to be in all versions of the product