If you are a trader looking to skim profit, absolutely, you take profit. I have stated I myself have taken money off the table no matter how undervalued I think this stock is and am now mostly playing with house money for the rest of what I believe to be very long ride over the next few years.
As for what the market does in the short term, who knows. The stock could fall 30% as much as it goes up 50%. There are no rules to what people do with their money.
Upgrades ARE perfect times to sell into strength if you are looking to get out at a top and yes, they generally come at short term tops. This stock is up 130% and aside from Jeffries, was not really given any upgrades(jeffries was 100 price target).
We have warm weather right now, plus our government acting like ajoke, raising of debt ceiling shenanigans....these are short term headwinds and can wreck havoc on a stock. But long term, people get up and go shopping and everything gets back to normal.
Best time to go shopping are during said sell-offs.