diff --git a/packages/core/test/unit/html/NodeProcessor.data.ts b/packages/core/test/unit/html/NodeProcessor.data.ts
index 102d265111..b255e4de57 100644
--- a/packages/core/test/unit/html/NodeProcessor.data.ts
+++ b/packages/core/test/unit/html/NodeProcessor.data.ts
@@ -36,6 +36,8 @@ export const PROCESS_PANEL_HEADER_SLOT_TAKES_PRIORITY_EXPECTED = `
 </panel>
 `;
 
+export const PROCESS_PANEL_HEADER_SLOT_TAKES_PRIORITY_WARN_MSG = "panel has a header slot, 'header' attribute has no effect.";
+
 export const PROCESS_PANEL_HEADER_NO_OVERRIDE = `
 <panel header="# Lorem ipsum" alt="**strong alt**">
   <div slot="header">
@@ -186,6 +188,9 @@ export const PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE_EXPECTED = `
 </popover>
 `;
 
+export const PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE_HEADER_WARN_MSG = "popover has a header slot, 'header' attribute has no effect.";
+export const PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE_CONTENT_WARN_MSG = "popover has a content slot, 'content' attribute has no effect.";
+
 /*
  * Tooltips
  */
@@ -317,4 +322,6 @@ export const PROCESS_DROPDOWN_HEADER_SLOT_TAKES_PRIORITY_EXPECTED = `
 </dropdown>
 `;
 
+export const PROCESS_DROPDOWN_HEADER_SLOT_TAKES_PRIORITY_WARN_MSG = "dropdown has a header slot, 'header' attribute has no effect.";
+
 /* eslint-enable max-len */
diff --git a/packages/core/test/unit/html/NodeProcessor.test.ts b/packages/core/test/unit/html/NodeProcessor.test.ts
index 371d1069f7..32f6d270fe 100644
--- a/packages/core/test/unit/html/NodeProcessor.test.ts
+++ b/packages/core/test/unit/html/NodeProcessor.test.ts
@@ -2,11 +2,20 @@ import path from 'path';
 import cheerio from 'cheerio';
 import htmlparser from 'htmlparser2';
 import * as testData from './NodeProcessor.data';
+import * as logger from '../../../src/utils/logger';
 import { Context } from '../../../src/html/Context';
 import { shiftSlotNodeDeeper, transformOldSlotSyntax } from '../../../src/html/vueSlotSyntaxProcessor';
 import { getNewDefaultNodeProcessor } from '../utils/utils';
 import { MbNode, parseHTML } from '../../../src/utils/node';
 
+jest.mock('../../../src/utils/logger', () => ({
+  warn: jest.fn(),
+}));
+
+beforeEach(() => {
+  jest.clearAllMocks();
+});
+
 /**
  * Runs the processNode or postProcessNode method of NodeProcessor on the provided
  * template, verifying it with the expected result.
@@ -42,12 +51,15 @@ const processAndVerifyTemplate = (template: string, expectedTemplate: string, po
 };
 
 test('processNode processes panel attributes and inserts into dom as slots correctly', () => {
+  const warnSpy = jest.spyOn(logger, 'warn');
   processAndVerifyTemplate(testData.PROCESS_PANEL_ATTRIBUTES,
                            testData.PROCESS_PANEL_ATTRIBUTES_EXPECTED);
   processAndVerifyTemplate(testData.PROCESS_PANEL_HEADER_SLOT_TAKES_PRIORITY,
                            testData.PROCESS_PANEL_HEADER_SLOT_TAKES_PRIORITY_EXPECTED);
+  expect(warnSpy).toHaveBeenCalledWith(testData.PROCESS_PANEL_HEADER_SLOT_TAKES_PRIORITY_WARN_MSG);
   processAndVerifyTemplate(testData.PROCESS_PANEL_HEADER_NO_OVERRIDE,
                            testData.PROCESS_PANEL_HEADER_NO_OVERRIDE_EXPECTED);
+  expect(warnSpy).toHaveBeenCalledWith(testData.PROCESS_PANEL_HEADER_SLOT_TAKES_PRIORITY_WARN_MSG);
 });
 
 test('processNode processes question attributes and inserts into dom as slots correctly', () => {
@@ -72,10 +84,13 @@ test('processNode processes quiz attributes and inserts into dom as slots correc
 });
 
 test('processNode processes popover attributes and inserts into dom as slots correctly', () => {
+  const warnSpy = jest.spyOn(logger, 'warn');
   processAndVerifyTemplate(testData.PROCESS_POPOVER_ATTRIBUTES,
                            testData.PROCESS_POPOVER_ATTRIBUTES_EXPECTED);
   processAndVerifyTemplate(testData.PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE,
                            testData.PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE_EXPECTED);
+  expect(warnSpy).toHaveBeenCalledWith(testData.PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE_HEADER_WARN_MSG);
+  expect(warnSpy).toHaveBeenCalledWith(testData.PROCESS_POPOVER_ATTRIBUTES_NO_OVERRIDE_CONTENT_WARN_MSG);
 });
 
 test('processNode processes tooltip attributes and inserts into dom as slots correctly', () => {
@@ -118,8 +133,10 @@ test('processNode processes dropdown header attribute and inserts into DOM as he
 });
 
 test('processNode processes dropdown with header slot taking priority over header attribute', () => {
+  const warnSpy = jest.spyOn(logger, 'warn');
   processAndVerifyTemplate(testData.PROCESS_DROPDOWN_HEADER_SLOT_TAKES_PRIORITY,
                            testData.PROCESS_DROPDOWN_HEADER_SLOT_TAKES_PRIORITY_EXPECTED);
+  expect(warnSpy).toHaveBeenCalledWith(testData.PROCESS_DROPDOWN_HEADER_SLOT_TAKES_PRIORITY_WARN_MSG);
 });
 
 test('markdown coverts inline colour syntax correctly', async () => {