ID 496877 - Adding a vertex map to a mesh resets all of the sculpting.

Problem summary
Adding a vertex map to a mesh resets all of the sculpting.

Customer reported version
modo.15.2v1

Customer reported platform
windows10

Steps to reproduce

1) Launch Modo.

2) Load customer provided scene.

3) Select sculpting(2) mesh.

4) In top left of the viewport enable Show Weight Maps.

5) In the item Properties section select the Vertex Maps tab.

6) Expand the Weight Maps and select Weights.

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7) Go to the the Brush menu of the Tool selection area and click on the Weight Map Tools tab.

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8) Click on paint as seen above and then attempt to paint the weight area on the sculpted mesh.

9) Observe that the sculpting is removed from the mesh.

Note: For further demonstration please view customer provided screen recording.

Expected behaviour
Painting the weight map on the sculpted mesh should just add weight map area.

Actual behaviour
Painting the weight on the sculpted mesh results in sculpting to be removed entirely.

Workaround
Unknown. If known please add steps to workaround or avoid the problem

Reproduced by support
This bug has been reproduced in:
15.2v1 - Windows 10
15.1v1 - Windows 10
15.0v1 - Windows 10
14.2v1 - Windows 10 - Regression



Unable to reproduce bug in:
14.1v2 - Windows 10


Earliest version tested
14.1v2 - This issue doesn't appear in this version and has regressed