Migration Utilities - Problems importing Feature Definitions

When Feature Definitions are exported and edited in Excel, all properties are working, except the link to the Feature Symbology after importing them:

Step 1)

Export Feature Definitions:

The Feature Symbology is filled in.

Step 2)

Use the Features XML to/from Excel tool to convert the xml to Excel:

Step 3)

I have to edit the properties, but for now, everything is un-edited.

Step 4)

Use the Features XML to/from Excel tool to convert the Excel to XML:

Step 5)

Import the Feature XML file:

Step 6)

Check if everything is imported:

In first instance everything seems to be imported. Looking to the Properties of the Feature Definitions however, shows that the Feature Symbology is empty:

This appears to all Feature Definition types (including in the Template Library).

What am I doing wrong?

OpenRoads 2021 R1

Latest Migration Utilities (2020 R3)

Regards Louis