When our site (using Cloudron) was upgraded to 2.0.0, twig within pages was no longer processed. (Twig in templates seems to be fine.)
To troubleshoot, I spun up a fresh install of Grav 2.0.0 and noticed the same thing.
In addition, in the Admin panel, Configuration > Content > Process only has Markdown as an option (even though I manually edited the system.yaml to include twig:true under pages:process.

Any sense of what is going on?