just do schema === 'untitled'

fixes #35083

src/vs/workbench/parts/files/browser/fileActions.ts

@@ -1374,7 +1374,7 @@ export abstract class BaseSaveOneFileAction extends BaseSaveFileAction {
 			source = toResource(this.editorService.getActiveEditorInput(), { supportSideBySide: true });
 		}
 
-		if (source && (this.fileService.canHandleResource(source) || this.untitledEditorService.exists(source))) {
+		if (source && (this.fileService.canHandleResource(source) || source.scheme === 'untitled')) {
 
 			// Save As (or Save untitled with associated path)
 			if (this.isSaveAs() || source.scheme === 'untitled') {
@@ -1391,7 +1391,7 @@ export abstract class BaseSaveOneFileAction extends BaseSaveFileAction {
 				const editor = getCodeEditor(activeEditor);
 				if (editor) {
 					const activeResource = toResource(activeEditor.input, { supportSideBySide: true });
-					if (activeResource && (this.fileService.canHandleResource(activeResource) || this.untitledEditorService.exists(source)) && activeResource.toString() === source.toString()) {
+					if (activeResource && (this.fileService.canHandleResource(activeResource) || source.scheme === 'untitled') && activeResource.toString() === source.toString()) {
 						viewStateOfSource = editor.saveViewState();
 					}
 				}