https://www.theregister.co.uk/2018/06/04/g_suite_misconfiguration_leaks_data/

If you're sysadmin of an organisation using Google Groups and G Suite, you need to revisit your configuration to make sure you aren't leaking internal information.

That advice comes from Kenna Security, which on June 1 said it found 31 per cent of a sample of 9,600 organisations leaking sensitive e-mail information.