Issue #2878556 by plach, matsbla, vijaycs85, Gábor Hojtsy, catch, gabesullice,...

Issue #2878556 by plach, matsbla, vijaycs85, Gábor Hojtsy, catch, gabesullice, effulgentsia, hchonov, hass, amateescu, xjm: Ensure that changes to untranslatable fields affect only one translation in pending revisions

(cherry picked from commit 27c3b40e)