I can also confirm this problem which is easily reproduced on Fedora 29 by moving an application to workspace 4 and restarting gnome-shell from workspace 4. I can restart gnome-shell from workspace 1 with no other workspaces in use which is why I thought that Fedora 29 didn't have this issue which I have seen in both Ubuntu 18.10 and Ubuntu 19.04 (the current development version).
I can also confirm this problem which is easily reproduced on Fedora 29 by moving an application to workspace 4 and restarting gnome-shell from workspace 4. I can restart gnome-shell from workspace 1 with no other workspaces in use which is why I thought that Fedora 29 didn't have this issue which I have seen in both Ubuntu 18.10 and Ubuntu 19.04 (the current development version).
My Ubuntu bug report is at https:/ /bugs.launchpad .net/ubuntu/ +source/ gnome-shell/ +bug/1796607