The bonding agent won't do squat as a moisture barrier; it's a form of glue. It's only there to make sure the bond between old concrete and new is sound.

All told, this looks bad but is probably ok.

That said, I am a person on Reddit. If you want sureity, hire a structural engineer who'll come out and let you know what's going on. The few hundred it'll cost will pay for itself if you ever sell the house and the buyers go "what's this?"