diff --git a/addons/addon-webgl/test/WebglAtlasOverflow.test.ts b/addons/addon-webgl/test/WebglAtlasOverflow.test.ts
index 98a4c5944..9f866122c 100644
--- a/addons/addon-webgl/test/WebglAtlasOverflow.test.ts
+++ b/addons/addon-webgl/test/WebglAtlasOverflow.test.ts
@@ -23,6 +23,7 @@ import {
   captureRowSignatures,
   expectSignatureMatches,
   loadWebglStrict,
+  resetMaxAtlasPages,
   setMaxAtlasPages,
   writeAndWaitForRender
 } from '../../../test/playwright/RendererTestUtils';
@@ -96,13 +97,7 @@ test.describe('atlas page overflow (#322756 class)', () => {
     } finally {
       ctx.page.off('pageerror', onError);
       // Restore the default so a lowered cap can never leak into other tests.
-      await ctx.page.evaluate(() => {
-        const renderer = (window as any).term._core._renderService._renderer.value;
-        const atlas = renderer?._charAtlas;
-        if (atlas) {
-          (atlas.constructor as any).maxAtlasPages = undefined;
-        }
-      }).catch(() => { /* page may already be unusable after a crash */ });
+      await resetMaxAtlasPages(ctx).catch(() => { /* page may already be unusable after a crash */ });
       await ctx.page.close();
     }
   });
diff --git a/addons/addon-webgl/test/WebglGlyph.test.ts b/addons/addon-webgl/test/WebglGlyph.test.ts
index c6cf260ea..dff2c275e 100644
--- a/addons/addon-webgl/test/WebglGlyph.test.ts
+++ b/addons/addon-webgl/test/WebglGlyph.test.ts
@@ -23,6 +23,7 @@ import {
   expectSignatureMatches,
   floodDistinctGlyphs,
   loadWebglStrict,
+  resetMaxAtlasPages,
   setMaxAtlasPages,
   waitForRender,
   writeAndWaitForRender
@@ -45,6 +46,9 @@ test.describe('WebGL glyph + atlas integrity', () => {
     await loadWebglStrict(ctx);
   });
 
+  // A lowered page cap must not leak into renderers built by later tests.
+  test.afterEach(async () => await resetMaxAtlasPages(ctx));
+
   test('renders distinct, non-blank glyphs', async () => {
     await writeAndWaitForRender(ctx, 'A W .');
     await assertTextureAtlasPresent(ctx);
diff --git a/addons/addon-webgl/test/WebglReproExperiment.test.ts b/addons/addon-webgl/test/WebglReproExperiment.test.ts
index 99034b940..67d64b9f2 100644
--- a/addons/addon-webgl/test/WebglReproExperiment.test.ts
+++ b/addons/addon-webgl/test/WebglReproExperiment.test.ts
@@ -14,7 +14,7 @@
  */
 import test, { expect } from '@playwright/test';
 import { ITestContext, createTestContext, openTerminal } from '../../../test/playwright/TestUtils';
-import { captureRowSignatures, expectSignatureMatches, getAtlasPageCount, loadWebglStrict, setMaxAtlasPages, writeAndWaitForRender } from '../../../test/playwright/RendererTestUtils';
+import { captureRowSignatures, expectSignatureMatches, getAtlasPageCount, loadWebglStrict, resetMaxAtlasPages, setMaxAtlasPages, writeAndWaitForRender } from '../../../test/playwright/RendererTestUtils';
 import { generateColoredAsciiFlood } from '../../../test/playwright/SyntheticTui';
 
 const HEADER = ' HEADER_REF_0123456789';
@@ -27,6 +27,9 @@ test.describe('single-terminal merge integrity (#322756 class)', () => {
   test.skip(({ browserName }) => browserName !== 'chromium');
   test.describe.configure({ timeout: 60000 });
 
+  // A lowered page cap must not leak into renderers built by later tests.
+  test.afterEach(async () => await resetMaxAtlasPages(ctx));
+
   test('pinned header renders identically across 30 merge-heavy body redraws', async () => {
     await openTerminal(ctx, { cols: 80, rows: 24 });
     await loadWebglStrict(ctx);
diff --git a/addons/addon-webgl/test/WebglSingleTermStress.test.ts b/addons/addon-webgl/test/WebglSingleTermStress.test.ts
index d4bbe9be4..fbe12d1bb 100644
--- a/addons/addon-webgl/test/WebglSingleTermStress.test.ts
+++ b/addons/addon-webgl/test/WebglSingleTermStress.test.ts
@@ -16,6 +16,7 @@ import {
   floodDistinctGlyphs,
   getAtlasPageCount,
   loadWebglStrict,
+  resetMaxAtlasPages,
   setMaxAtlasPages,
   waitForRender,
   writeAndWaitForRender
@@ -37,6 +38,9 @@ test.describe('WebGL single-terminal heavy render + merge', () => {
     await loadWebglStrict(ctx);
   });
 
+  // A lowered page cap must not leak into renderers built by later tests.
+  test.afterEach(async () => await resetMaxAtlasPages(ctx));
+
   test('heavy merge churn must not crash the GlyphRenderer (vscode#322756)', async () => {
     // Guard: heavy merges must not throw from GlyphRenderer.render. Note the
     // page cap here is lowered AFTER the renderer was built, so _atlasTextures
diff --git a/test/playwright/RendererTestUtils.ts b/test/playwright/RendererTestUtils.ts
index a3862c77f..e6d1e8593 100644
--- a/test/playwright/RendererTestUtils.ts
+++ b/test/playwright/RendererTestUtils.ts
@@ -292,6 +292,23 @@ export async function setMaxAtlasPages(ctx: ITestContext, maxAtlasPages: number)
   expect(applied, 'should be able to reach the texture atlas to set maxAtlasPages').toBe(true);
 }
 
+/**
+ * Resets `maxAtlasPages` to undefined so the next constructed renderer re-derives it from GL
+ * capabilities. Call after any test that used {@link setMaxAtlasPages}: the static lives for
+ * the page's lifetime, so without a reset every terminal opened later in the same file builds
+ * its GL texture and shader sampler arrays at the lowered cap.
+ * @param ctx The test context.
+ */
+export async function resetMaxAtlasPages(ctx: ITestContext): Promise<void> {
+  await ctx.page.evaluate(() => {
+    const renderer = (window as any).term?._core?._renderService?._renderer?.value;
+    const atlas = renderer?._charAtlas;
+    if (atlas) {
+      (atlas.constructor as any).maxAtlasPages = undefined;
+    }
+  });
+}
+
 /**
  * Writes `chunks` screenfuls of distinct glyphs, rendering after each chunk.
  *