ID 431846 - Expression linking a Shuffle2 in/out knobs to another channels knob crashes Nuke

Problem summary
Expression linking a Shuffle2 in/out knobs to another channels knob crashes Nuke

Customer reported version
nuke.12.1v2

Customer reported platform
centos7

Steps to reproduce

1) Create a Shuffle2 and a Grade node

2) Click the in1 knobs link menu button > Set link

3) Set the expression to: Grade1.channels

4) Press OK, Nuke crashes

Expected behaviour
For Nuke to fail to link the knobs, as although they are both Channel_Knobs, one has more controls than the other

Actual behaviour
Nuke Crashed

Reproduced by support
This bug has been reproduced in:

Nuke 12.1v2 - Windows 10, macOS 10.14, CentOS 7*

Nuke 12.1v1 - Windows 10, macOS 10.14, CentOS 7*

*CentOS didn;t always crash sometimes it just hangs and fails to do anything else

Earliest version tested
Nuke 12.1v1 - This feature did not exist before this version