essentially the efficient-market hypothesis at work.
Selling on news is common and so is selling into a run. Normally they happen together.
Some food for thought, and again i dont know the stock. But with all the better than expected PRs the last day or two could have raised investor expectation of today's PR, when the PR came out investors found that it was inline with their last week expectations they were forced and was not as good as their current expectations then the stock price will decline. Then you throw in emotional sell offs, profit takers, and people trying to secure profit or minimize losses, and a few bad rumors around the message boards and you have the workings for a shatty day
Just some food for thought presented to you in a probably poorly structured paragraph thats difficult to read

lol