User blog comment:RyuuseiR3/Bushiroad TCG Strategy Presentation 2019/@comment-33734015-20190209012443/@comment-27282915-20190209012841

The most common consensus for the hiatus is that the animation company that did the animation for the Buddyfight anime was bought by another company. I'd imagine that a company shift like that would need a lot of time to sort out the paperwork especially if there's some contract renegotiations that need to be figured out.

Other opinions seems less credible in light of that.