The test is failing in Blink and WebKit: https://test.csswg.org/shepherd/testcase/first-line-floats-002/spec/css21/name/first-line-floats-002/ Might be duplicated of bug #140313 (but I'm not 100% sure).
Created attachment 460303 [details] Safari 15.5 differs from Firefox but matches Chrome I am able to reproduce this bug in Safari 15.5 on macOS 12.4 using following link: Link - https://test.csswg.org/shepherd/repository/d6ef85a87b368138c3221dcb78ef3986b2fa54a7/css21/selectors/first-line-floats-002.xht Please refer to attached screenshot for other browsers. Chrome Canary 105 follows Safari 15.5, while Firefox shows expected result and render the output in "GREEN". Thanks!