These two sentences (which are not in sequence) come from a text from the Tobira Gateway to Advanced Japanese textbook. They both seem broadly similar to me in structure, therefore I don't understand why 日本人の会話 takes に, while 日本語の会話 takes で as particle.
I'm unsure if the difference come from the particles themselves or from 見られる. I had supposed maybe they used different particles because in the first one, the passive 見られる has 日本人の会話 as indirect object, and in the second one, 日本語の会話で is used with a potential 見られる, and japanese conversations are where 文の倒置 can bee seen. But I believe my logic might be overly complicated.
I have seen other questions in regards to に and で and their differences, and I do think I comprehend how they differ when it comes to "action happening in physical location", but as this isn't the case, I could not figure it out more from those questions.
So, why do they take different particles, despite the structure of these sentences being seemingly close to each other?