i have WRK plus software CE9.9.0 register to expressway core, CMS trunk to core, and mcu 4210 also register as SIP to core.
when WRK plus call out/in to MCU 4210, it appears media quality icons (refers to codian help, it means there is media quality issue in WRK+) but there were no packetloss or error status. the video quality so bad very low resolution (but from call status shows good, it getting 4CIF)
then i tried WRK join to CMS, it works normally, video quality HD.
I can recall hearing about this issue, but don't have access to my documentation at the moment. I believe this was one of the issues that was resolved in CE9.10.0, so try upgrading your endpoint and trying again.
Wayne -- Please remember to mark helpful responses and to set your question as answered if appropriate.