When adding a “yes” tag to post it’s automatically converted to “true” and displayed that way. It does not change when tag is compound, e.g. “say yes”.
For instance in my markdown I have
tags: [yes, stain, texture]
and when it render itself then “yes” is changed for “True”.
Sounds like a parser issue that converts 1, on, yes, true to true. Which makes sense in a configuration file, not in front matter. Probably worth filing an issue on GitHub.