ID 419992 - Lock stacked UVs command doesn't work

Problem summary
Lock stacked UVs command doesn't work

Customer reported version
modo.13.2v1

Customer reported platform
windows10

Steps to reproduce

1) Download and open the attached file in Modo.
2) Go to UV layout and in the menu select Pack...

3) In the menu that appears enable Lock Stacked and deselect Orient and then select OK.

4) Notice that it isn't packed as expected.

Expected behaviour
The stacked UVs should stay together when using the Lock Stacked command.

Actual behaviour
The stacked UVs do not stay together.

Workaround
Unknown.

Reproduced by support

This bug has been reproduced in:

13.2v1 - Windows 10, CentOS 7, MacOS 10.13 -regression

Unable to reproduce bug in:

13.1v1 - Windows 10, CentOS 7, MacOS 10.13

Earliest version tested

13.1v1 - This issue doesn't appear in this version and has regressed.