This problem occurs for me too. I think it's an issue with Safari rather than Edge. I started using Chrome and set it as my default browser to prevent this.
Hope this helps.
This is a bug. But we are still working out if it has to be resolved with safari or Edge animate. Will keep you posted on the updates.
As a workaround please set Chrome or Opera or Firefox as default browser, the alert window will no longer displayed. Chrome and Opera are webkit browsers.
Please check and let me know if it works.