The black box is more mysterious to me. I had a client for whom I managed a G-Suite account with a custom domain name. The domain was not on a blacklist, and

The black box is more mysterious to me. I had a client for whom I managed a G-Suite account with a custom domain name. The domain was not on a blacklist, and things generally worked well. One day a colleague and I discovered that he had not received some of my emails (intra-domain - me@example.com to him@example.com). This is all within the confines of Google. Google had flagged some messages as spam, and by what determination I could not fathom. The content seemed perfectly typical. I have had really pleasant experiences with G-Suite human support, at least in terms of the quality of interaction. But they could not answer why some intra-domain emails were being flagged as spam. I have suspicions that it would take a whole team of G engineers to maybe identify what bit of logic in their systems (incorrectly) marked some of the emails as spam. It seems the beast (automation) is just almost not under their control anymore.