ID 416614 - Viewing R3D files in the file browser will cause one CPU thread to always be at 100% utilisation

Problem summary
Viewing R3D files in the file browser will cause one CPU thread to always be at 100% utilisation, even if the file is not actually read into Nuke. This happens until Nuke is closed.

Customer reported version
Nuke 12.0v3

Customer reported platform
CentOS 7

Steps to reproduce

1) Open Nuke

2) Create a Read node

3) Turn on the preview panel and scrub through on footage.

4) Press 'Cancel' on the file browser

5) Open the system monitor and look at the CPU usage. One thread will be at 100%, but it may jump around between threads until Nuke is closed:

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Expected behaviour
Viewing a R3D file in the file browser should not cause any threads to be at 100%.

Actual behaviour
One CPU thread will always be at 100% utilisation after viewing a R3D file in the file browser, even if the file is not actually read into Nuke. This happens until Nuke is closed.

Reproduced by support
This bug has been reproduced in:
Nuke 12.0v3 - Windows 10 - Linux CentOS 7
Nuke 12.0v1 - Windows 10 - Linux CentOS 7 - Regression

Unable to reproduce bug in:
Nuke 11.3v6 - WIndows 10 - Linux CentOS 7

Earliest version tested
Nuke 11.3v6
- This issue doesn't appear in this version and has regressed