Blizzard has increased the hourly instance limit per Battle.net account to 10, after some players were locked out on their alt characters. This should allow a total of 10 runs across various characters per Battle.net account.
Earlier today, we doubled the hourly instance limit for the Headless Horseman event.
Read more on wowhead.com
The website gamebastion.com is an aggregator of news from open sources. The source is indicated at the beginning and at the end of the announcement. You can send a complaint on the news if you find it unreliable.