ID 497390 - An error occurs when stopping playback with multiple MotionBlur nodes upstream.

Problem summary
An error occurs when stopping playback with multiple MotionBlur nodes upstream.

Customer reported version
13.0::13.0v5

Customer reported platform
10.14

Steps to reproduce
1) In Nuke, create a ColorWheel node, and set keyframes in the rotate knob to have an animation.
2) Add a Shuffle node, and change the B input to Motion, then connect any channels.
3) Add two MotionBlur nodes.
5) Play the timeline and immediately stop the playback.

Expected behavior
The Viewer should render the frames without issue when multiple GPU devices are in use.

Actual behavior
An error appears in the Viewer as: "MotionBlur1: Error running on multiple devices."

​

Workaround
Disabling the "Use GPU if available" knob allows the renders to complete.

Reproduced by Support in:
Nuke 13.1v1 - macOS 11.6 BigSur (2x AMD Firepro D600)
Nuke 13.0v1 - macOS 11.6 BigSur (2x AMD Firepro D600)
Nuke 12.1v1 - macOS 11.6 BigSur (2x AMD Firepro D600)

Unable to reproduce bug in:
Nuke 12.0v7 - macOS 11.6 BigSur (2x AMD Firepro D600)
Nuke 13.1v1 - Windows 10, CentOS 7 (2x GTX 1080ti)
Nuke 13.1v1 - macOS 10.15 Catalina (single GTX or AMD cards)

Earliest version tested
Nuke 12.0v7 - This issue doesn't appear in this version and has regressed - Nuke would crash prior to 12.1v1.