Its probably nitpick correct, because the 12GW is planned capacity, while the solar might be measured use? but simple assumptins or conversions, as another comment points out, get you comparable numbers. taking the title into account, the whole article is a little bit smoke and mirrors on clear communication, despite having plenty of numbers. Thats a shame because it sounds like even unvarnished its good results!
The world did add 3GW of nuclear generation in 2025 but it also closed 3GW.