Session timeout and invoice payment

In version 6.0, on the gtk client, if we leave open an invoice posted in its tab for a while for more than 10min and we come back to it to pay it, we have 2 empty dialog boxes which open and block the client (this does not happen on sao and the user’s password is requested)

Has anyone observed this behavior before?

I tried on Linux and Windows and the client correctly popup the authentication dialog for me.