Was Triage X supposed to end after only 10 episodes? Was Triage X supposed to run for only 10 episodes? I could have sworn that when I first added this to my queue on MyAnimeList, it was listed to run for 12 episodes.

Did something happen (like lack of funding), or did I just misread the number and it was only going to run for 10 episodes all along?
According to the following article on ANN (dated 20 March, 2015, more than 2 weeks before the anime airs), it was confirmed that Triage X was listed at 10 episodes:


  A flyer at the AnimeJapan 2015 event's business day lists the television anime of Shoji Sato's Triage X manga as 10 episodes long, along with an original video animation (OVA) episode.


I also googled with queries such as トリアージX 話数 and トリアージX 全12話 (the second one is an attempt to dig out any article claiming 12 episodes), limited to articles posted before April, but all Japanese websites list the series at 10 episodes.

Since there is no evidence that the wrong information had been posted elsewhere on the Internet, it's probably due to MyAnimeList populating the wrong information, or a lapse in your memory.