ID 467312 - Linked knobs do not update when using the first_frame or last_frame values of Root.

Problem summary
Linked knobs do not update when using the first_frame or last_frame values of Root.

Customer reported version
nuke.12.2v2

Customer reported platform
windows10

Steps to reproduce

1) In Nuke, add a Grade node.

2) Select any node knob and add the expression: root.first_frame

3) Open the Project Settings (S) on the node graph, then change the first frame of the project.

4) View the knob in the Grade node for changes.

Expected behavior

The knobs should update immediately for the changed frame.

Actual behavior
The knob does not update until after changing another component ro knob in Nuke.

Workaround
A Python addKnobChanged() callback to update the knobs works as anticipated:

def rootFirstChange():    if nuke.thisKnob().name() == "first_frame":        fps = nuke.root()["fps"].value()        nuke.root()["fps"].setValue(fps +1)        nuke.root()["fps"].setValue(fps)def rootLastChange():    if nuke.thisKnob().name() == "last_frame":        fps = nuke.root()["fps"].value()        nuke.root()["fps"].setValue(fps +1)        nuke.root()["fps"].setValue(fps)nuke.addKnobChanged(rootFirstChange, nodeClass="Root")nuke.addKnobChanged(rootLastChange, nodeClass="Root")

Reproduced by Support in:
Nuke 12.2v5 - Windows 10, CentOS 7

Nuke 12.2v1 - Windows 10

Nuke 12.1v1 - Windows 10

Nuke 12.0v1 - Windows 10

Nuke 11.0v1 - Windows 10

Nuke 10.0v1 - Windows 10

Nuke 9.0v1 - Windows 10

Nuke 8.0v1 - Windows 10, CentOS 7

Earliest version tested
Nuke 8.0v1 - This issue appears to be in all versions of the product