the issue with Sokol is that he bought his shares a month or two before the buyout. Buffett has held through ups and downs for nearly 3 years, much like Munger had with BYD before Berkshire came in as 10% owner. So BYD is the analogy, not Sokol and Lubrizol.
Buffett always had the ultimate say on the Lubrizol deal...if it was nixed, Sokol was left holding Lubrizol stock. Sokol was not guaranteed that Lubrizol would be bought by Berkshire.
Buffett holds SRG directly in his personal account. Whether he held those shares for 1 year or 10 years is irrelevant, as he holds the decision to fund the SRG term loan. It's not about disclosure, it's about the stock moving likely upwards as financing risk is removed. If the SRG stock had been held by Berkshire, then that's perfectly fine.
It's pretty clear as the nose on your face that this deal actually holds more conflict than the Sokol/Lubrizol deal. I expect there is something that has not been disclosed, because I think the conflict here would be very discernable to Buffett and Munger.
Someone commented on the JPM investment, but that is less relevant, because Berkshire may already have held too much in bank-related stocks with their large positions in WFC and BAC. We know Buffett buys small amounts of many stocks, simply to receive the annual reports, and that he was a big fan of Dimon's. JPM's stock movement was not predicated on any influence by Berkshire, so while it may have annoyed shareholders that he didn't buy any JPM for Berkshire, it also isn't really a conflict.
Cheers!