Created attachment 437256 [details] Demonstration of the failure. When compared to a fully-inline element, checkbox descendants of a flexbox set to align on baseline do not appear on a consistent baseline. (I don't presume to specify which of these two checkboxes is in the wrong location, but they cannot both be right.)
Created attachment 437257 [details] Screenshot of the unaligned checkboxes.
- Chrome: Alignment is consistent. - Firefox: https://bugzilla.mozilla.org/show_bug.cgi?id=1728976
Yeah there is still a lot of work pending to be done in baseline alignment for flexbox.
<rdar://problem/82975177>