If a diff uploaded on phabricator is rejected by person A in the initial state, then the diff updated to a new version and accepted by person B, things seem to reach an unclear state:

• phabricator Differential webpage of the diff shows the state as "[ ] Needs Review" (so checkbox untoggled, see picture below)
• phabricator Differential overview page lists the diff under "Waiting on Review"
• arc tells on trying to land the diff: "Revision 'Dxyz: [...] ' has not been accepted. Continue anyway? [y/N]"
• sKreamer also claims "[Needs Review]" when showing info on the diff

So either the webpage renderer for the Diff should toggle the checkbox, or perhaps the state of "Conflicting reviews" needs to be introduced and supported. Something to handle for upstream.