Problem summary When adding channels to a layer (eg, going from 2 channels to 4 channels), existing shuffle and shuffle copy nodes which presume the previous channel number change their output.
This appears to be a long standing issue that is present in Nuke 12, 11 etc. and happens on all platforms.
Customer reported version Nuke 11.3v5
Customer reported platform CentOS 7
Steps to reproduce
1) Open the attached script, and observe the output of the Shuffle1 node, and the channels available to select in the Shuffle1 properties - This script contains a customer layer (newlayer), with 2 channels - red and alpha.
2) Read the newlayer.exr file into this script - The read node contains a layer called newlayer, with 4 channels - red, green, blue and alpha
3) Observe how the output, and the selected channels of the Shuffle1 node has now changed
Expected behaviour Adding new channels to a layer should not change the output of existing Shuffle and ShuffleCopy nodes
Actual behaviour Adding new channels to a layer changes the output of existing Shuffle and ShuffleCopy nodes
Reproduced by support This bug was found by our developers.