ID 381457 - When the number of frame server processes is set to more than 1, some scripts will fail to render via Frame Server

Problem summary
Some scripts may cause Nuke to fail to render them with the frame server. This only seems to occur when the number of frame server processes is set to more than 1.

It appears that .tmp files will be created but the render seems either reach 100% with errors or will get stuck in the Background Renders queue indefinitely.

Customer reported version
Nuke 11.2v4

Customer reported platform
macOS 10.13

Steps to reproduce

1) Open Nuke and open the attached script.

2) Render the script, ensuring that frame server is enabled.

3) Notice that .tmp files have been created but the render seems to either reach 100% with errors or will get stuck in the Background Renders queue indefinitely.

Workaround
Rendering without using the frame server still seems to work and you could also execute a background render via Python, like so:

writeNode = nuke.toNode('Write1')
nuke.executeBackgroundNuke("C:\Program Files\Nuke11.3v1\Nuke11.3.exe", [writeNode], nuke.FrameRanges('1-100'), ['main'], {'maxThreads':36, 'maxCache':'42G'})

Reproduced by support

This bug has been reproduced in:
Nuke 11.3v2 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Nuke 11.2v5 - Windows 10

Nuke 11.1v6 - Windows 10

Nuke 11.0v4 - Windows 10

Nuke 11.0v1 - Windows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Earliest version tested
Nuke 11.0v1 - Windows 10
-Frame server wasn't implemented into Nuke until 11.0v1.

Expected behaviour
The script should render successfully from the frame server.

Actual behaviour
The script will fail to render when using frame server. The render seems to either reach 100% with errors or will get stuck in the Background Renders queue indefinitely.