XO 6.7.0 went out on 30 July, and the changelog carries Bastien's fix under Backups as "Fix failed status on successful retry", pointing at PR https://github.com/vatesfr/xen-orchestra/pull/10129 and back at this thread: https://xen-orchestra.com/blog/xen-orchestra-6-7/.
Given what you said about keeping the backup XOA on a version you trust, I would not rush it, but that is the version to look for when you do move.
I have not exercised the retry path myself, so if a retried VM still reports the job as failed after you upgrade, it is worth saying so here.