After RTC is upgraded from 6.0.6 to 6.0.6.1, obtained rtc_cm:state through OSLC return 500 code

 When we are in RTC 6.0.6 ifix015, we can use the OSLC protocol to access through the following URL to return the status of the workitem (<dc:title>New</dc:title>, this New is the literal value of the status)
GET https://clmserver/ccm/oslc/workitems/123456/rtc_cm:state

The returned message is as follows:
<rtc_cm:Status rdf:about="https://clmserver/ccm/oslc/workflows/_HdsP8BTFEeqpBb4-kiZcxw/states/com.ibm.team.workitem.defectWorkflow/com.abcdefg.team.workitem.workflow.dft.state .s1">
<dc:identifier>com.abcdefg.team.workitem.workflow.dft.state.s1</dc:identifier>
<dc:title>New</dc:title>
<rtc_cm:iconUrl>
https://clmserver/ccm/service/com.ibm.team.workitem.common.internal.model.IImageContentService/processattachment/_HdsP8BTFEeqpBb4-kiZcxw/workflow/new.gif
</rtc_cm:iconUrl>
<rtc_cm:group>open</rtc_cm:group>
</rtc_cm:Status>

But after upgrading to 6.0.6.1 ifix011, the same method returned a code of 500. as follows:

<oslc_cm:error>
<oslc_cm:status>500</oslc_cm:status>
<oslc_cm:message/>
</oslc_cm:error>


The same problem, there is rtc_cm:resolution attribute.

Is the related API interface changed in V6.0.6.1 and is no longer compatible with the original calling method?