ID 414089 - DeepMerge2 produces artefacts when there are Deep samples that intersect, and the alpha equals 1

Problem summary
DeepMerge2 produces artefacts when there are Deep samples that intersect, and the alpha equals 1.

This issue appears to have been introduced into Nuke 12 with the DeepMerge2 node.

Customer reported version
Nuke 12.0v1

Customer reported platform
Windows 10

Steps to reproduce

1) Open Nuke and open the attached script:

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The script is contains two cubes, and a DeepExpression is used on each to make the samples overlap.

2) View the result of the DeepMerge:

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Actual behaviour
Intersecting samples do not merge together correctly. There are also artefacts in the areas where the intersection happens. 


Expected behaviour
The samples should merge together correctly, as they did in Nuke 11 - there also shouldn't be any artefacting.
The following image shows the result of the equivalent script in Nuke 11.3v6:

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Workaround
Enabling "drop hidden samples" on the DeepMerge seems to resolve this issue.

Reproduced by support
This bug has been reproduced in:
Nuke 12.0v2 - WIndows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)
Nuke 12.0v1 - WIndows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra) - Regression

Unable to reproduce bug in:
Nuke 11.3v6 - WIndows 10 - Linux CentOS 7 - macOS 10.13 (High Sierra)

Earliest version tested
Nuke 11.3v6
- This issue doesn't appear in this version and has regressed. The DeepMerge2 node also did not exist before Nuke 12.0v1.