Dotnet Cover - running in Ubunto 20 - we are unable to disable parallelization when running

When running Dotnet cover for C# Projects in Ubuntu 20 - we are unable to disable parallelization. it does work pretty well in windoes but in Linux not mattre the configuration/setting/annotations. it always run in parallel

I tried 3 methods. 

disable parallelization  using runsetting 

Method 1

<RunSettings>
<RunConfiguration>
   <DisableParallelization>true</DisableParallelization>
</RunConfiguration>
<!-- Configurations that affect the Test Framework -->
<DataCollectionRunSettings>
   <DataCollectors>
     <DataCollector friendlyName="XPlat Code Coverage">
       <Configuration>
         <Exclude>
           <File>**\*Test*.cs</File> <!-- Exclude test files -->
         </Exclude>
       </Configuration>
     </DataCollector>
   </DataCollectors>
</DataCollectionRunSettings>
</RunSettings

Method 2: running dotnet cover with disable parallel as argument

Method 3: usin annottaions