They got it from the shopDisney website for the limited edition attraction poster, which is a reliable source. Things change all the time but shopDisney is an official website, Inside the Magic was just reporting the information.
“Celebrate the new aquatic adventure at the reimagined Epcot with this limited edition print promoting the forthcoming Moana-inspired Journey of Water walkthrough maze. Featuring the goddess Te Fiti from the 2016 movie, the poster is printed on archival paper and will whet your appetite for the attraction’s 2021 opening at Walt Disney World.”
“Journey of Water inspired by Moana is scheduled to open at Epcot in 2021.”
After the poster sold out, shopDisney edited the copy to say "forthcoming...walkthrough maze."
Things change all the time but Disney seems confident in moving forward with it based on the original description and selling the poster in the first place. Plus, it was never a huge budget "attraction" to begin with. Like someone else said, it's basically a waterfall and some jumping fountains.