Webex App for VDI is working with fallback mode, instead of VDI-optimized mode.
When virtual channel allow list policy is enabled, add the Webex app virtual channel (CSCOTM) to the allow list with the virtual channel name and process path: "CSCOTM,C:\Program Files\Cisco Spark\dependencies\teamshvdagent.exe".
Starting with Citrix Virtual Apps and Desktops 7 2109, virtual channel allow lists are enabled by default. When enabled, only Citrix virtual channels are allowed.