At 21:50 he also discusses the "big acquisition rumor" involving Sony. According to him, it's bigger than Kojima Productions. So even if Kojima Productions is acquired by Sony at some point, what he and Greg Miller were talking about is not that.
Middler from VGC chimed in on the rumor as well. As you can see, he reiterated what Grubb and Miller said on that podcast. That it's unverifiable. As they were saying, the sources they have would be second hand. Not from the people directly involved. He then goes on to say that it would cause mass hysteria.
He goes further. He, Miller, and Grubb agreed that whoever the rumor is surrounding, it shouldn't be repeated. So whatever it is these three are saying they've heard a rumor of, it's really not a good idea for it to get out.