Earlier quoted context omitted.
IDK how Google flight is a serious option when any complex query (2 layovers on obscure route) always ends up with "oops the price you've seen before isn't available anymore" or you need to "Call agent" to get realistic price.
I've noticed the "oops the price changed" a lot recently, but prior it was rock solid for years for me (mostly European airlines/flights)
The other gem is squeezing an economy class leg into otherwise business class search. And it's not the inevitable 2 hour connection. It's the entire 12 hour flight that they think you'll not notice before booking.