In #21 it was noticed that a check run failure was a false negative; the image snapshots produced by Playwright were imperceptibly different, but showed a 0.04 ratio of pixel differences.
The use of ubuntu-latest unavoidably means that subtle updates to Linux and the Chromium version it comes with could produce binary differences in images created, and evidently Playwright is sensitive to this.
Playwrights settings for screenshots allow for a maxDiffPixelRatio to be set, to allow slight fuzziness; which should mitigate the issue.