It isnt. It is the next arc that have low page counts
Edit: I just looked, only 2 chapters are 15 and one is 13, the rest is over 15
We're talking a stretch of chapters from 184-190, yes? 7 chapters with page counts of 17, 17, 19, 16, 13, 15, and 15. The last couple pages of that 13 page chapter are mostly just reaction shots, which is why I remembered it being quite short.
At any rate, that's without a doubt a lower average page count than previous arcs. We definitely were seeing a decline in page count at this point. Take the hideout raid for example, which is about 14 chapters with majority being 19 pages and none (at least that I saw at a cursory glance) being fewer than 17. Those 14 chapters were adapted into 5 episodes. I'm just saying, it's not out of the question to see 7 chapters, more or less half of which are on the shorter side, make it into two or two and a half episodes depending on how it all gets adapted.