ID 593440 - MatchGrade's "Auto Detect" Pre LUT option ignores the node's Mask

Problem summary:
MatchGrade's "Auto Detect" Pre LUT option ignores the node's Mask 
 
Customer reported version:
Nuke 15.1v5
 
Customer reported platform:
Windows 10
 
Steps to reproduce:
1) Download the attached match_grade_auto.nk file and launch NukeX.
2) Double click both MatchGrade nodes to open their Properties, and press the Analyze Reference Frames button for each.
3) Then, press the Write button for both MatchGrade nodes to create a CSP file from each.
4) Open the mg_1.csp and mg_2.csp files in a text editor and observe their differences: 
 
mg_1.csp (Logarithmic):

32-0.003035 -0.001702 -0.000143 0.001680 0.003810 0.006302 0.009215 0.012620 0.016602 0.021257 0.026700 0.033064 0.040505 0.049204 0.059375 0.071266 0.085170 0.101426 0.120431 0.142653 0.168633 0.199009 0.234524 0.276047 0.324595 0.381357 0.447721 0.525313 0.616032 0.722098 0.846109 0.991100 0.000000 0.032258 0.064516 0.096774 0.129032 0.161290 0.193548 0.225806 0.258065 0.290323 0.322581 0.354839 0.387097 0.419355 0.451613 0.483871 0.516129 0.548387 0.580645 0.612903 0.645161 0.677419 0.709677 0.741935 0.774194 0.806452 0.838710 0.870968 0.903226 0.935484 0.967742 1.000000 32-0.003035 -0.001702 -0.000143 0.001680 0.003810 0.006302 0.009215 0.012620 0.016602 0.021257 0.026700 0.033064 0.040505 0.049204 0.059375 0.071266 0.085170 0.101426 0.120431 0.142653 0.168633 0.199009 0.234524 0.276047 0.324595 0.381357 0.447721 0.525313 0.616032 0.722098 0.846109 0.991100 0.000000 0.032258 0.064516 0.096774 0.129032 0.161290 0.193548 0.225806 0.258065 0.290323 0.322581 0.354839 0.387097 0.419355 0.451613 0.483871 0.516129 0.548387 0.580645 0.612903 0.645161 0.677419 0.709677 0.741935 0.774194 0.806452 0.838710 0.870968 0.903226 0.935484 0.967742 1.000000 32-0.003035 -0.001702 -0.000143 0.001680 0.003810 0.006302 0.009215 0.012620 0.016602 0.021257 0.026700 0.033064 0.040505 0.049204 0.059375 0.071266 0.085170 0.101426 0.120431 0.142653 0.168633 0.199009 0.234524 0.276047 0.324595 0.381357 0.447721 0.525313 0.616032 0.722098 0.846109 0.991100 0.000000 0.032258 0.064516 0.096774 0.129032 0.161290 0.193548 0.225806 0.258065 0.290323 0.322581 0.354839 0.387097 0.419355 0.451613 0.483871 0.516129 0.548387 0.580645 0.612903 0.645161 0.677419 0.709677 0.741935 0.774194 0.806452 0.838710 0.870968 0.903226 0.935484 0.967742 1.000000 

 
mg_2.csp (Linear):

2-0.003035 0.9911000.0 1.02-0.003035 0.9911000.0 1.02-0.003035 0.9911000.0 1.0

 
Expected behavior:
If a Mask is provided to a MatchGrade node, exported CSP files should be identical when the region inside the Mask is unchanged.
 
Actual behavior:
When a MatchGrade node's Pre LUT knob is set to "Auto Detect", the Mask option is ignored and it seems that the entire image is used to determine the Pre LUT instead.
 
Workaround:
No known workaround at this time.
 
Reproduced by Support in:
NukeX 15.1v5 - Windows 10, macOS 14 Sonoma
NukeX 14.0v1 - Windows 10
NukeX 13.0v1 - Windows 10
NukeX 12.0v1 - Windows 10
 
Earliest version tested:
NukeX 12.0v1 - This issue appears to be in all tested versions of the product