ID 376284 - Reloading a Read Node while the ScanlineRender is rendering, causes Hangs [ WINDOWS ONLY ]

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Problem summary
Users have been experiencing a "hanging" issue with EXR Read nodes.
From our testing, we have been successful in reproducing the issue when the ScanlineRender is attempting to render the footage.
 
Nuke will hang until what appears to be the ScanlineRender to finish the initial render.

This issue occurs without the EXR footage being available, so it is a read pathing issue.

From tests, this is a Windows specific issue.

Customer reported version
nuke.10.5v7

Customer reported platform
windows10

Steps to reproduce

1) Open the script attached to this report. ( Nuke hangs for multiple minutes, wait it out )

2) View the "Merge1" node. 
 
3) While the Node is rendering, select and View a Read node  ( use read11 for this test ).

4) Within the Read node, set the "on_error" node to 'checkerboard' and press the "reload" button.

Result: Nuke will hang for anywhere between a few seconds, to multiple minutes.

            Any Interaction with the software will cause the Window to not respond and turn White ( Windows test )


Workaround
Unknown.

Reproduced by support
This bug has been reproduced in:
Nuke11.3v1 - Windows 7
Nuke11.2v5 - Windows 7
Nuke11.2v1 - Windows 7
Nuke11.1v1 - Windows 7
Nuke11.0v1 - Windows 7
Nuke10.5v1 - Windows 7
Nuke10.0v1 - Windows 7
Nuke9.0v1 - Windows 7
Nuke8.0v1 - Windows 7


Unable to reproduce bug in:
Nuke11.2v4 - Mac10.13 - CentOS7

Earliest version tested
- This issue appears to be in all versions of the product - Windows ONLY

Expected behaviour
Read nodes should load almost instantly. 

Actual behaviour
Read nodes ( even with no footage connected ), load super slow.
 

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