I do not have the option to "Moderate space" on a space that belongs to a team that I created and I am a moderator of. This is also the case for other people I have added as team members and promoted to moderators of the team. I imagine this has to be some sort of licensing issue but I can't find anything to help explain.
Screenshots from desktop and web:
I understand that spaces that don't belong to teams can't be moderated and this is not the case.
Related:
Moderating spaces in a team (webex.com)
Solved: "Moderate space" not showing up on Webex spaces - Cisco Community
