Is "false concedence" a thing? If not, is there an established term?
The idiom agree to differ (disagree) may fit this question: TFD
Of two parties, to mutually accept that they simply do not (and will not) share the same view on a particular issue, in the interest of moving past the issue or avoiding further confrontation.
The OED cites this 1699 usage:
1699 R. Ferguson Just & Modest Vindic. Scots Design 202 If we agree to differ in Religious Matters of less Importance, we might thereupon possibly better accord.