When I insert a template, my YAML is modified. Even when the `Properties view` is disabled

Even if you have disabled properties view, still all YAML management done both by Obsidian and by the plugins is handled by the library we use.
The reasons for the way it acts are outlined here API: processFrontMatter removes string quotes, comments, types, formatting - #6 by Licat.

The properties view can be disabled, but still Obsidian and the plugins interact with the YAML via this parser.