When using fontSize: "s" in the EUI data grid gridStyle prop, extra text content is visible below where the truncation occurs.

Discover:

EUI examples:

MRE: https://codesandbox.io/p/sandbox/fervent-khayyam-lfppgv?file=%2Fdemo.js

From a quick search, it looks like this may be related to the -webkit-line-clamp CSS property plus the cell content element's padding resulting in more content being visible than expected: https://stackoverflow.com/questions/70211893/why-is-line-clamp-not-working-with-padding.