diff --git a/packages/mermaid/src/diagrams/flowchart/flowDb.ts b/packages/mermaid/src/diagrams/flowchart/flowDb.ts
index a1637eb2b..c3cc82841 100644
--- a/packages/mermaid/src/diagrams/flowchart/flowDb.ts
+++ b/packages/mermaid/src/diagrams/flowchart/flowDb.ts
@@ -92,7 +92,9 @@ export class FlowDB implements DiagramDB {
       case 'text':
         return labelType;
       default:
-        return 'markdown';
+        // For flowcharts, default to 'text' (v10 behavior: only explicit markdown is rendered)
+        // This is different from v11 where undefined defaulted to 'markdown'
+        return 'text';
     }
   }
 
@@ -1043,7 +1045,6 @@ You have to call mermaid.initialize.`
         assetWidth: vertex.assetWidth,
         assetHeight: vertex.assetHeight,
         constraint: vertex.constraint,
-        diagramType: 'flowchart', // Add diagram type for rendering decisions
       };
       if (isGroup) {
         nodes.push({
@@ -1111,7 +1112,6 @@ You have to call mermaid.initialize.`
         dir: subGraph.dir,
         isGroup: true,
         look: config.look,
-        diagramType: 'flowchart', // Add diagram type for rendering decisions
       });
     }
 
@@ -1158,7 +1158,6 @@ You have to call mermaid.initialize.`
         animate: rawEdge.animate,
         animation: rawEdge.animation,
         curve: rawEdge.interpolate || this.edges.defaultInterpolate || config.flowchart?.curve,
-        diagramType: 'flowchart', // Add diagram type for rendering decisions
       };
 
       edges.push(edge);
diff --git a/packages/mermaid/src/rendering-util/rendering-elements/clusters.js b/packages/mermaid/src/rendering-util/rendering-elements/clusters.js
index d78787a25..4f49bd5d6 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/clusters.js
+++ b/packages/mermaid/src/rendering-util/rendering-elements/clusters.js
@@ -10,16 +10,6 @@ import createLabel from './createLabel.js';
 import { createRoundedRectPathD } from './shapes/roundedRectPath.ts';
 import { styles2String, userNodeOverrides } from './shapes/handDrawnShapeStyles.js';
 
-function shouldRenderClusterLabelAsMarkdown(node) {
-  const diagramType = node.diagramType;
-
-  if (diagramType === 'flowchart') {
-    return node.labelType === 'markdown';
-  }
-
-  return node.labelType !== 'text' && node.labelType !== 'string';
-}
-
 const rect = async (parent, node) => {
   log.info('Creating subgraph rect for ', node.id, node);
   const siteConfig = getConfig();
@@ -41,7 +31,7 @@ const rect = async (parent, node) => {
   const labelEl = shapeSvg.insert('g').attr('class', 'cluster-label ');
 
   let text;
-  if (shouldRenderClusterLabelAsMarkdown(node)) {
+  if (node.labelType === 'markdown') {
     text = await createText(labelEl, node.label, {
       style: node.labelStyle,
       useHtmlLabels,
diff --git a/packages/mermaid/src/rendering-util/rendering-elements/edges.js b/packages/mermaid/src/rendering-util/rendering-elements/edges.js
index 9b65ec621..c759bc127 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/edges.js
+++ b/packages/mermaid/src/rendering-util/rendering-elements/edges.js
@@ -44,27 +44,18 @@ export const getLabelStyles = (styleArray) => {
   return styles;
 };
 
-function shouldRenderEdgeLabelAsMarkdown(edge) {
-  const diagramType = edge.diagramType;
-
-  if (diagramType === 'flowchart') {
-    return edge.labelType === 'markdown';
-  }
-
-  return edge.labelType !== 'text' && edge.labelType !== 'string';
-}
-
 export const insertEdgeLabel = async (elem, edge) => {
   let useHtmlLabels = evaluate(getConfig().flowchart.htmlLabels);
 
-  const labelElement = shouldRenderEdgeLabelAsMarkdown(edge)
-    ? await createText(elem, edge.label, {
-        style: getLabelStyles(edge.labelStyle),
-        useHtmlLabels,
-        addSvgBackground: true,
-        isNode: false,
-      })
-    : await createLabel(edge.label, getLabelStyles(edge.labelStyle), undefined, false);
+  const labelElement =
+    edge.labelType === 'markdown'
+      ? await createText(elem, edge.label, {
+          style: getLabelStyles(edge.labelStyle),
+          useHtmlLabels,
+          addSvgBackground: true,
+          isNode: false,
+        })
+      : await createLabel(edge.label, getLabelStyles(edge.labelStyle), undefined, false);
 
   log.info('abc82', edge, edge.labelType);
 
diff --git a/packages/mermaid/src/rendering-util/rendering-elements/shapes/util.ts b/packages/mermaid/src/rendering-util/rendering-elements/shapes/util.ts
index ccd450205..5911f8f34 100644
--- a/packages/mermaid/src/rendering-util/rendering-elements/shapes/util.ts
+++ b/packages/mermaid/src/rendering-util/rendering-elements/shapes/util.ts
@@ -8,15 +8,6 @@ import { evaluate, sanitizeText } from '../../../diagrams/common/common.js';
 import { decodeEntities, handleUndefinedAttr, parseFontSize } from '../../../utils.js';
 import type { D3Selection, Point } from '../../../types.js';
 
-function shouldRenderAsMarkdown(node: Node): boolean {
-  const diagramType = node.diagramType;
-  if (diagramType === 'flowchart') {
-    return node.labelType === 'markdown';
-  }
-
-  return node.labelType !== 'text' && node.labelType !== 'string';
-}
-
 export const labelHelper = async <T extends SVGGraphicsElement>(
   parent: D3Selection<T>,
   node: Node,
@@ -51,7 +42,7 @@ export const labelHelper = async <T extends SVGGraphicsElement>(
   }
 
   let text;
-  if (shouldRenderAsMarkdown(node)) {
+  if (node.labelType === 'markdown') {
     text = await createText(labelEl, sanitizeText(decodeEntities(label), getConfig()), {
       useHtmlLabels,
       width: node.width || getConfig().flowchart?.wrappingWidth,
diff --git a/packages/mermaid/src/rendering-util/types.ts b/packages/mermaid/src/rendering-util/types.ts
index 65dec70f5..c8439b534 100644
--- a/packages/mermaid/src/rendering-util/types.ts
+++ b/packages/mermaid/src/rendering-util/types.ts
@@ -32,7 +32,6 @@ interface BaseNode {
   labelType?: string; // REMOVE? Always use markdown string, need to check for KaTeX - ⏳ wait with this one
 
   domId?: string; // When you create the node in the getData function you do not have the domId yet
-  diagramType?: string; // Used to determine diagram-specific rendering behavior
   // Rendering specific properties for both Flowchart and State Diagram nodes
   dir?: string; // Only relevant for isGroup true, i.e. a sub-graph or composite state.
   haveCallback?: boolean;
@@ -146,7 +145,6 @@ export interface Edge {
   source?: string;
   target?: string;
   depth?: number;
-  diagramType?: string; // Used to determine diagram-specific rendering behavior
 }
 
 export interface RectOptions {