I have a strange problem with one Kirby installation.
I open Site Options through the panel, then change the content of some fields, then hit Save. But the fields revert back to the original content and don’t save my current update.
It only happens to one of the two local MAMP kirby installations I am running.
But site.txt is the only file that is not writable? Have you checked on the file level if the content is saved and you just don’t see it in the panel? Are there any other text files in /content?