Blue
Ravenous Bugblatter Beast of Traal
I agreed with everything you said, except this.Because everyone understands (hopefully) it isn't RAI, even if it is RAW.
I'm not saying it's definitely rules as intended. But for this to be an accident, then two changes needed to be made, in very different parts of the book. If it was a single change, I'd agree it's likely a mistake. But multiple changes seems harder to be seen as anything except an intentional change.
Now, what would help show it's not RAI is if "hostile" was removed from other places as well, so it might be a global search & replace that they didn't double check. Like the (in)famous Encyclopedia Magicka where they replaced "mage" with "wizard" but didn't limit it to whole words, so every example of "damage" became "dawizard".
But if other "hostiles" are still there, then making two targeted changes in different parts of the book are hard to dismiss as anything except intentional.