ID 370616 - Mirrored Transformed footage merged OVER reformatted footage causes flickering effect within the Nuke Viewer Window

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Problem summary
When Merging OVER a Transformed, Mirrored input, onto a Reformatted input, Nuke11.2's Viewer window flickers when playing back the footage.

This issue is regressive, Nuke11.0 does not display the flicker problems.

Customer reported version
nuke.11.2v3

Customer reported platform
centos7

Steps to reproduce

1) Open the attached script ( open your script )

2) Set the Viewer to the Merge node connecting the inputs

3) Playback the footage

Result:     The Viewer will flicker constantly.

When the Merge node inputs are flipped, you can see that the footage is constantly switching between mirrored and no mirror


Workaround
     
1.  Modify the Merge operation to another merge type  ( issue only occurs with Over )


2.  Pre-composite the reformatted footage and remove the Reformat node.

3.  Disable 'Black Outside' on the Transform node.

4.  Add a very minor motion blur to the Transform node  ( set the motionblur knob to "0.000001" )

Reproduced by support

This bug has been reproduced in:
Nuke11.2v4 - Windows 7 - Mac10.13 - CentOS6.9
Nuke11.2v1 - Windows 7 - Mac10.13 - CentOS6.9
Nuke11.1v4 - Windows 7 - Mac10.13 - CentOS6.9
Nuke11.1v1 - Windows 7 - Mac10.13 - CentOS6.9 - regression

Unable to reproduce bug in:
Nuke11.0v4 - Windows 7 - Mac10.13 - CentOS6.9
Nuke10.5v7 - Windows 7 - Mac10.13 - CentOS6.9

Earliest version tested
- This issue no longer appears in this version and has regressed

Expected behaviour
Viewer should display smooth animation of the footage

Actual behaviour
Footage displayed constantly flickers between mirrored and non-mirrored

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