just received a letter yesterday from Mazda (see attached) saying that my limited powertrain warranty has been extended to 10 years or 120,000. it looks like it will apply to 2016 - 2020 CX-9, 2019 - 2020 CX-5 & 2018 - 2020 Mazda 6 vehicles equipped with a Skyactive-G 2.5T (Turbocharged) engine ("Covered Vehicle").
I'm assuming that this is just extended from your original warranty & not from when they replace the engine. I saw a post on here from a 2016 CX-9 owner who had his engine replaced in 2019 @ 70K & now his new engine is having the same issue, but he's at 150K & they are trying to determine if he qualifies for the extended warranty (I had my 2018 engine replaced in 2022 with 38.5K). All I know is I will probably be looking for another car before this extended warranty ends.