ID 580859 - "Error Running Kernel" with Pixel-Wise kernels with fewer number of channels being requested downstream than BlinkScript's output

Problem summary
BlinkScript kernels are failing to run when recompiling the kernel when the output of the BlinkScript is set to RGBA and the downstream node is requesting less than RGBA, like a Write or Viewer node just requesting RGB channels

Customer reported version
nuke.15.1v1

Steps to reproduce

1) Launch Nuke

2) Create a CheckerBoard node and connect a BlinkScript node

3) In the BlinkScript node, paste the following Kernel:

kernel Test : ImageComputationKernel<ePixelWise> {Image<eRead, eAccessPoint> src;Image<eWrite, eAccessPoint> dst;void process()  {    dst() = src();  }};

4) Set the Viewers channels knob to rgb

5) Recompile the kernel

Expected behaviour
For the requests channels to be displayed

Actual behaviour
The BlinkScript node errors saying: Error running kernel

Workaround
Set the output channels in the BlinkScript node to match what is being requested downstream, and update the BlinkScript code to only output an image with than many channels.

Create an Expression node downstream of the BlinkSCript node to forcibly request all the upstream channels:

Expression {expr0 rexpr1 gexpr2 bexpr3 aname Expression1}

Reproduced by support
This bug has been reproduced in:
Nuke 15.1v1 - Window 10 - regression

Unable to reproduce bug in:
Nuke 15.0v4 - Windows 10

Also reproduced by the Nuke development team

Earliest version tested
Nuke 15.0v4 - This issue doesn't appear in this version and has regressed