ID 410716 - Modifying base mesh of a multi-res sculpt corrupts the mesh

Problem summary
Deleting or bevelling a polygon in the base mesh of a multi-res sculpt destroys sculpt

Customer reported version
modo.13.1v1

Customer reported platform
windows10

Steps to reproduce

1. Open Modo.

2. Open the attached file.

3. Delete or bevel any polygon.

4. The mesh is now blocky and messed up.

Expected behaviour
When bevelling or deleting a polygon the entire mesh should not be affected

Actual behaviour
If you delete or bevel a polygon the mesh becomes corrupted.

Workaround

1. Select the polygon you wish to delete and an extra polygon on the mesh

2. Delete the two selected polygons

3. Mesh should be corrupted, press CTRL+Z to undo

4. Select the original polygon you wish to delete by itself

5. Delete the one polygon

Reproduced by support

This bug has been reproduced in:
13.1v1 - Windows 10 - CentOS 7 - macOS 10.14.5
13.0v1 - Windows 10 - CentOS 7 - macOS 10.14.5
12.2v2 - Windows 10 - CentOS 7 - macOS 10.14.5
12.1v2 - Windows 10 - CentOS 7 - macOS 10.14.5
12.0v1 - Windows 10 - CentOS 7 - macOS 10.14.5
11.2v3 - Windows 10 - CentOS 7 - macOS 10.14.5
11.1v1 - Windows 10 - CentOS 7 - macOS 10.14.5
11.0v3 - Windows 10 - CentOS 7 - macOS 10.14.5
10.2v4 - Windows 10 - CentOS 7 - macOS 10.14.5

Earliest version tested
10.2v4 - This issue appears to be in all versions of the product