After segmentation, a Task containing ICE Matches displays them as CM (Context Match) segments when opened in Online Editor:



After exporting the Task to a WSXZ package and opening it in in Trados Studio, the segments that were in CM status in WorldServer and Online Editor now display as PM (Perfect Match) segments:



Those segments are not supposed to be translated so they are left untouched. I create a Return package and import it back to WorldServer.  I open my Task in Online Editor. The segments that were in Context Match status before I exported the Task to a WSXZ package and imported the package back now display as 100% Matches. By clicking on that status, I can see the origin, which is no longer Context Match but Exact Match now:



The correct behaviour would be for those segments to

1- Keep the status CM (Context Match) in the SDLXLIFF file exported with the WSXZ package and display them in that status in Trados Studio
2- The segments should remain in their original status (Context Match) in Online Editor after the import of the Studio Return package. 
 

There is one setting in FTS, more specifically in the Sdl.WorldServer.FileTypeSupport.Server.HostProcess.exe.config file that controls how those ICE Match/Content Match segments display in Studio. Per default, it is set to make those segments display as PM (Perfect Match) segments. This is the reason for the issue: once the segment status/leverage is set to PM (Perfect Match) in the SDLXLIFF file inside the WSXZ package, when the same SDLXLIFF file is imported back as Return package, the previous status (CM) is overridden by the status PM (Perfect Match). However, this inconsistent behaviour can be easily changed. To do so, follow these steps:

1- On the WoldServer server where FTS is installed, find the Sdl.WorldServer.FileTypeSupport.Server.HostProcess.exe.config file, open it in Notepad++ and find this section in the file:

-->
    <add key='filetypedefinitioncache_max_count' value='256'/>
    <!-- Determines if ice-matches will be exported as perfect matches -->
    <!-- <add key="ExportIceAsPerfectMatch" value="true" /> -->
    <!-- Determines if Studio context matches should be imported back to WorldServer
         as ICE matches. -->
    <!-- <add key="ImportContextMatchAsIce" value="false" /> -->
    <!-- The number of times to retry FTS transactions in the event of database deadlocks or
         communication errors.
     -->

As you can see, this property is set to true per default: <add key="ExportIceAsPerfectMatch" value="true" />

2- Now change the value of the property and add it below the section, like this:

-->     <add key='filetypedefinitioncache_max_count' value='256'/>     
<!-- Determines if ice-matches will be exported as perfect matches -->     
<!-- <add key="ExportIceAsPerfectMatch" value="true" /> -->     
<!-- Determines if Studio context matches should be imported back to WorldServer          
as ICE matches. -->     
<!-- <add key="ImportContextMatchAsIce" value="false" /> -->     
<!-- The number of times to retry FTS transactions in the event of database deadlocks or          
communication errors.      -->

<add key="ExportIceAsPerfectMatch" value="false" />

3- Save your change in the file and restart the SDL File Type Server Service. 

After this change, the CM (Content Match) segment status between Online Editor and Trados Studio will match. After exporting to WSXZ package, the CM (Context Match) segments will no longer display as PM (Perfect Match, but as CM (Context Match) in Trados Studio as well. Moreover, after importing the Return package the status CM (Context Match) is kept as it was in Online Editor.

Configuration needs to be changed for the status to match.

Relevant article:

WorldServer - how is an ICE Match segment displayed in Trados Studio once exported from WorldServer as a WSXZ package? Is it possible to change its status from PM (Perfect Match) to CM (Context Match?