Hi @Anonymous,
Do you login in Microsoft Flow with your Microsoft Flow account within Microsoft Teams?
When you firstly open Microsoft Flow within Microsoft Teams, you need to login in Microsoft Flow with your Office 365 account. I have made a test on my side and don't have the issue that you mentioned. My flow's configuration as below:
The Approval shows up within Approval tab of Microsoft Teams as below:
Please take a try to click "Flows" tab within Flow integration panel of Microsoft Team, check if all flows that you owned show up within it. If not, please check if you have signed in Microsoft Flow within your Microsoft Teams.
In addition, please take a try to clear cache of your browser and open your Microsoft Teams, then reopen Flow integration within your Microsoft Teams and sign in Microsoft Flow to check if the issue is solved.
More details about Flow integration in Microsoft Teams, please check the following article:
https://flow.microsoft.com/en-us/blog/microsoft-flow-in-microsoft-teams/
Best regards,
Kris