The manga has been on a string of these hiatuses lately, even matching the two kings of hiatuses in Hunter x Hunter’s Yoshihiro Togashi and Berserk’s Kentarou Miura.
Arakawa has actually been planning to end the manga, and has been heading to its “imminent” climax since 2015.
However, her hiatuses has more to do with her other (and more important) duty, and that is as a mother.
However, the frequent hiatuses have slowed down the manga’s end.