I would say it is because they made a big marketing blog post about it at the time[1] (August 2025). So clearly they considered it a significant new feature.
The blog post ended with the words "If we don’t spot any major regressions with 1.86, the next stable release will likely turn on state encryption by default for all new nodes". It was then enabled by default 1.90.2 onwards (October 2025).
That is why I would consider it a significant u-turn.