coffee, interesting stories.
In the first one, Rav may understand better than the kid how important relationship with mechutonim are long-term, so it might be time for the kulos. All concerns about mechutonim kashrus level shold have been addressed before the shiduch.
In the 2nd story, Rabonim may have relied on hazoka – everything from that mshgiach or around them is always kosher. And maybe, also, any sofek could create a medauraite problem of ruining the simcha.