After you close Workspace/exit the flatpak, the container will still be running. If you re-enter the container/re-launch Workspace, Workspace will hang. To prevent this, you need to use flatpak kill to stop the container after you've closed workspace.
If you do end up running into the bug and Workspace starts hanging, you can fix it by deleting the contents of ~/.var/app/ca.dcloud.ICAClient/.ICAClient/.tmp
After you close Workspace/exit the flatpak, the container will still be running. If you re-enter the container/re-launch Workspace, Workspace will hang. To prevent this, you need to use flatpak kill to stop the container after you've closed workspace.
If you do end up running into the bug and Workspace starts hanging, you can fix it by deleting the contents of ~/.var/app/ca.dcloud.ICAClient/.ICAClient/.tmp