Hi, I can help with this.
Is it extremely cold where this occured?
Was the rear defroster on?
You are sure that nothing hit the window?
I have seen this happen a few times , we had an Odyssey not long ago do this.
If the glass is cold and the defroster has a damaged or defective line in the grid it can create a hot spot and cause the window to blow out.
In the case of the Odyssey it was covered by warranty. You just need to tell them exactly how it happened.
Can they check the wiring to see if it was scratched or if the damage was always present?
There is no way to check if the window is destroyed, It cant really be determined either way.
If they dont seen willing to cover it, you can call Honda and ask for goodwill coverage.
The customer service number is XXXXX your owners manual.