Rubrik posted better-than-expected quarterly results. So, why did its stock get crushed?Rubrik (RBRK -17.68%) stock suffered a big valuation pullback in Wednesday's trading. The company's share price sank 18.1% the day of trading following the release of its second-quarter report.Rubrik published its Q2 results after the market closed yesterday and posted mixed performance. The data-security specialist posted sales and earnings that were much better than expected, but investors seem to have concerns about i ...