Test 1:
I tried this to no avail.
Wether the cfgxxx.tmp-file contains <Language ID="MatchOS" /> or <Language ID="nl-nl" /><Language ID="MatchOS" /> it doesn't make any difference.
Test 2.
I used the ODT with the following .XML file, but also then I see 2 entries in the installed software section:
<Configuration>
<Add OfficeClientEdition="64" Channel="Deferred" MigrateArch="TRUE">
<Product ID="O365ProPlusRetail">
<ExcludeApp ID="Access" />
<ExcludeApp ID="Groove" />
<ExcludeApp ID="InfoPath" />
<ExcludeApp ID="Lync" />
<ExcludeApp ID="OneNote" />
<ExcludeApp ID="Publisher" />
<ExcludeApp ID="SharePointDesigner" />
<ExcludeApp ID="Teams" />
<Language ID="MatchOS" />
</Product>
</Add>
<Display Level="None" AcceptEULA="TRUE" />
<Property Name="SharedComputerLicensing" Value="0" />
<ExecCount xmlns="http://schemas.microsoft.com/intune">1</ExecCount>
<LastExecuteTime xmlns="http://schemas.microsoft.com/intune">2/2/2021 2:38:01 PM</LastExecuteTime>
</Configuration>