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The problem lies in "clear_scopes" settings

There is also a bug associated with the folder name containing characters like ()! + etc.  This happens when you create/upload a folder on the webdav server. Tested on Yandex, and Dropbox via DropDav service

Quickly new beta! Yes problem is gone!

Every first launch of Textastic. iPhone SE. Latest iOS/Textastic Beta

I think Textastic already has built-in Sublime Text Symbol Definition for sublime-syntax files from PackageDev, but it is based on YAML and works correctly unlike Json-based files

It's custom syntax from Sublime Text PackageDev repo. All json-based files like sublime-color-scheme, sublime-completions, 

sublime-menu etc, have a black-colored braces, commas and some comment lines.

If you insert whitespace characters after them (see gif), they are highlighted correctly.

For example, for sublime-color-scheme, you can choose to define the sublime text color scheme syntax

Please keep an eye at some json-based syntaxes from PackageDev

Strange things with curly braces and commas. 

Sent! But i have this bug with 'built-in' css.json