I think it is down because the risk/reward ratio was wrong. With such a high P/E ratio what is the upside, in the short term anyway? The downside though could be high. Same probably applies to Naspers, although I have not done much research on either, so dont take my advice, these are just my thoughts.
On the other hand, I have just had an experience with Gooderson, a hotel stock nobody wanted, you could have bought as much as you wanted at 39c up until tuesday this week. It had a NAV of 154c and PE of 11 at 39c. It is now 60c on a plan to delist at 65c. Admittedly this stock caused me some headaches, and I just wrote about it in my blog if you interested
http://www.dividendtycoon.com/blog/2016/07/15/my-hotels-are-almost-sold-a-lucky-escape-for-this-dividend-tycoon/ The point though is that what was there to loose for the risk at 39c, and what was the upside? The best stocks are not always good investments and the worst are not always bad. I would encourage anybody to read Howard Marks book on investing in this regard.