Regex Doesn't Recognise Non-Latin Characters as "Word Characters"

[someonenameguy]

The Regex engine currently being used seems to not recognise non-Latin characters. Thus, see "word Boundary" in the middle of words.

Example: napušavali the see the š as an non-word character and matches \bavail in napu\bš\bavali.

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Oddly regex101 show that the Rust Regex Crate shouldn't do that:

Javascript Regex does though: