My views are more in line in with what Daring Fireball stated about the release:
"However, Apple could wait until October to launch the 10.5-inch iPad, in order to avoid spoiling the the design of the much-rumored "iPhone 8" with an edge-to-edge OLED display, which is expected to be announced in September."
I also think Apple will announce it during September and have it release later as they did with the 12.9 Pro.
On a side note, Apple has been Announcing certain products (Airpods, Nike Watch, iPad 12.9 Pro) and launching them at a later date. I'm not saying that has any pertinence here, but it's been somewhat of a trend.
http://daringfireball.net/2017/03/about_that_10_point_5_inch_ipad