The same thing that hit VE in T169272: [Regression pre-wmf.8] VE crashes while opening Gallery and some other dialogs also broke CX2 translation view:
load.php?debug=true&lang=fi&modules=jquery%2Cmediawiki&only=scripts&skin=vector&version=0otr805:3869 Uncaught TypeError: Cannot read property 'toggleClass' of undefined at mw.cx.widgets.PageTitleWidget.OO.ui.Widget.setDisabled (Widget.js:84) at mw.cx.widgets.PageTitleWidget.OO.ui.InputWidget.setDisabled (InputWidget.js:210) at new mw.cx.widgets.PageTitleWidget (mw.cx.ui.PageTitleWidget.js?e79c0:22) at mw.cx.ui.SourceColumn.render (mw.cx.ui.SourceColumn.js?6d862:48) at mw.cx.ui.SourceColumn.init (mw.cx.ui.SourceColumn.js?6d862:32) at new mw.cx.ui.SourceColumn (mw.cx.ui.SourceColumn.js?6d862:24) at new MwCxUiColumns (mw.cx.ui.Columns.js?7d227:12) at mw.cx.ui.TranslationView.render (mw.cx.ui.TranslationView.js?dbb0e:45) at mw.cx.ui.TranslationView.init (mw.cx.ui.TranslationView.js?dbb0e:38) at new mw.cx.ui.TranslationView (mw.cx.ui.TranslationView.js?dbb0e:24)
I'm filing this task as I cannot yet see expected follow-ups: Either fix the regression or proactively find the places that are broken and alert the maintainers and guide them with fixing.