ID 511171 - Frame values appear incorrect when using the [frame] expression in the Particle Expression node and viewed with the ParticleInfo node.

Problem summary
Frame values appear incorrect when using the [frame] expression in the Particle Expression node and viewed with the ParticleInfo node.
 
Customer reported version
Nuke 13.2v1
 
Customer reported platform
macOS 10.15 Catalina
 
Steps to reproduce
1) In NukeX, copy/paste the following script in the Node Graph:

ParticleEmitter { start_frame 1 lifetime 100 spread 0.43 color 0 name ParticleEmitter1 selected true xpos 6 ypos -74 } ParticleExpression { sizeexpr "\[frame]" name ParticleExpression1 selected true xpos 6 ypos -48 } ParticleInfo { showSize true maxParticles 10 name ParticleInfo1 selected true xpos 6 ypos -10 }

3) View the Particle Info node and it's Properties.
4) Move the playback head and view the frame output in the Viewer.
 

 
Expected behavior
The [frame] expression should be accurate for the frame viewed on the timeline.
 
Actual behavior
The output of the [frame] expression is off by at least 1 number. It potentially gets offset by more frames when used in a longer expression such as [frame] > 55? 10:1
 
Workaround
There is no available workaround at this time.
 
Reproduced by Support in:
Nuke 13.2v2 - Windows 10, CentOS 7
Nuke 13.2v1 - Windows 10
Nuke 13.1v1 - Windows 10
Nuke 12.1v1 - Windows 10, CentOS 7
 
Unable to reproduce bug in:
Nuke 12.0v8 - Windows 10, CentOS 7
 
Earliest version tested
Nuke 12.0v8 - The ParticleInfo node feature did not exist before the reproduced version