That’s just one of those ambiguous statements. Strictly speaking, it is correct, “get ready to ‘turn left and then turn right’” which is two separate turns, but some people like to think it’s confusing when it actually isn’t. The “and” pulls together two distinct turns into a single sentence. Waze does not say, “get ready to turn left but then turn right” but that’s what people want to hear I guess.
“Be ready to turn left followed by a right turn” would be less ambiguous.
I consider that queueing to be very accurate and correct. I hear that and I am ready to not only turn left at the noted distance, but then be prepared to turn right.
Waze is not suggesting that you prepare for turning one direction only to turn the other. It never has.
I’m glad I brought this topic up. It seems that many people are tripped up by the grammar. I think the goal of having the distance instruction first makes perfect sense but trying to use a casual form of speech seems to be frustrating for some. I’ve been managing just fine after switching from “including street names” to “directions only (with themes)” as the navigation guidance setting but would still like to see(or hear) the correct grammar being used.