Munger and Lu turned Buffett on to byb , it's definitely Buffett's trade.

Why do you conclude that?

It seems pretty clear that it was Mr Munger's original pick/suggestion.
It was certainly not an investment whose scale along screamed "Mr Buffett's pick", so that is no guide.
It wasn't a very big position to begin with, under $250m?

My guess has always been that the investment was pretty much entirely the action of (delegated to) Mr Munger and/or Mr Sokol.
It wasn't big enough for Mr Buffett to care that much, like any pick by T&T, and it was left outside his main portfolio within the insurance division.
Offhand, my impression is that Mr Buffett's involvement was limited to "I don't particularly object".

Once the capital at risk became appreciable after the gains, and with lofty valuation levels, taking the money off the seems more like a Buffett decision.
Especially, as others noted, with the high and increasing jurisdiction risk.

Jim