According to a report from MNR Daily, the creators of the "Attack on Titans" anime series are adamant to halt production for season 2 until the manga source material has completed the necessary story arcs for them to adapt.

The report points out that the anime studios are still waiting for the manga to be at least four story arcs ahead before they even begin production for the second season. This was decided on in order to prevent the anime from deviating from the manga's intended story direction and to avoid the need of adding in unnecessary filler.

It was previously reported that the four story arcs that the anime is waiting for may be the final story arc as well for "Attack on Titan," meaning the anime series will only have two seasons in total. This may change if there is the decision to expand on the story by exploring side-stories and past events in a potential third season.

The report also states that by waiting, the studios will be able to avoid the negative feedback that the live-action films have suffered from. Many fans were disappointed not only because of the lackluster pacing and visual effects but also because how the movies strayed so far from the story of the manga and anime series.

Both of the live-action films have strayed far from the source material, eventually creating their own stream of events that have almost nothing to do with the "Attack on Titan" original storyline. 

Season 2 is expected to further explore the history of the Titans and how they came to be and it is explained that Ymir has a lot to do with their origins. The Royal Family is also getting a larger role and there will be a civil war that will break out that will sooner or later depose the current king.

The trailer for the aforementioned live action film can be viewed below: