Deploy Addins - Button "Save" is not there when conscenting to Add-In rights

Hey all,

I am quite puzzled at the moment: I try to upgrade an Addin manifest like I've done it a hundret times before. After uploading the manifest and defining the target group I get to the screen to give permission that the app may have the rights given in the manifest. But I can't get further in the dialog than this:

Tried with another addin, tried with another tenant, same result. Has anyone a hint what I am missing here?

Thanks,

Carsten