ID 422642 - TimeBlur node not writing out blur correctly when using an Expression node

Problem summary
TimeBlur node not writing out blur correctly when using an upstream Expression node

Customer reported version
nuke.11.2v5

Customer reported platform
windows10

Steps to reproduce

1) Open Nuke

2) Add a CheckerBoard node

3) Add an STMap node below the Checkerboard node

4) Add a TimeBlur node below the STMap node

5) Add an Expression node and connect it to the STMap node

6) Open the Expression node and enter the following

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7) Notice that it plays normally in the viewer

8) Add a Write node under the TimeBlur and write out the Sequence

9) Clear cache and import outputted sequence

10) Result will be no TimeBlur on written out sequence

Expected behaviour
There should be TimeBlur on the written out sequence

Actual behaviour
There is no effect applied to the sequence

Workaround
If the calculation of the expression is done within an external node, then fed back in as a knob value this will avoid the issue.

 

To do this from the current example:

 

1) Create a NoOp node

 

2) Within the NoOp node, add a new user 'floating point slider' knob named 'Random Frame'

 

3) When created, alter the expression of the Random Frame knob to the existing expression

 

4) Within the Expression node replace the expression with the knob value.

 

Result: When rendering, the TimeBlur will be applied.

Reproduced by support
This bug has been reproduced in:

Nuke 12.2v3 - Windows 10 - CentOS 7 - macOS 10.14

Nuke 12.0v3 - Windows 10 - CentOS 7 - macOS 10.14
Nuke 11.0v1 - Windows 10
Nuke 10.0v1 - Windows 10
Nuke 9.0v1 - Windows 10
Nuke 8.0v1 - Windows 10 - CentOS 7 - macOS 10.14

Earliest version tested
Nuke 8.0v1 - This issue appears to be in all versions of the product