a) failing to truncate on a code point sequence boundary (a bug React Native iOS used to have)[1], and
b) failing to truncate on a grapheme cluster boundary (a bug React Native Android seems to still have)[2]
[1]: https://adam-p.ca/blog/2025/04/string-length/#utf-16-code-un...
[2]: https://adam-p.ca/blog/2025/04/string-length/#unicode-code-p...