diff --git a/lib/plugins/teams.js b/lib/plugins/teams.js
index da97a2d2e..94d2fef5e 100644
--- a/lib/plugins/teams.js
+++ b/lib/plugins/teams.js
@@ -7,7 +7,14 @@ module.exports = class Teams extends Diffable {
     this.log.debug(`Finding teams for ${this.repo.owner}/${this.repo.repo}`)
     return this.github.paginate(this.github.rest.repos.listTeams, this.repo).then(res => {
       this.log.debug(`Found teams ${JSON.stringify(res)}`)
-      return this.checkSecurityManager(res)
+      return this.checkSecurityManager(res).then(teams => {
+        // GitHub's team `name` is the display name, which can differ from `slug` (what config
+        // entries and comparator()/changed() actually match on). Normalizing `name` to `slug` here
+        // keeps the nop-mode diff (MergeDeep.compareDeep, which pairs array items by `name`) in sync
+        // with the real add/update/remove decisions, which are always slug-based. This must happen
+        // after checkSecurityManager(), which matches on the real display `name`.
+        return teams.map(team => ({ ...team, name: team.slug }))
+      })
     })
   }
 
diff --git a/test/unit/lib/plugins/teams.slug-fix.test.js b/test/unit/lib/plugins/teams.slug-fix.test.js
new file mode 100644
index 000000000..0886a78ec
--- /dev/null
+++ b/test/unit/lib/plugins/teams.slug-fix.test.js
@@ -0,0 +1,112 @@
+// Regression test for: Teams plugin nop-mode diff reports phantom additions/deletions
+// for teams whose GitHub display `name` differs from their `slug` (e.g. "Platform
+// Engineering" vs. `platform-engineering`), even when nothing has actually changed.
+//
+// Fixes: https://github.com/github-community-projects/safe-settings/issues/1033
+const any = require('@travi/any')
+const Teams = require('../../../../lib/plugins/teams')
+
+describe('Teams - slug vs display name nop diff', () => {
+  let github
+  const org = 'bkeepers'
+  const teamSlug = 'platform-engineering'
+  const teamDisplayName = 'Platform Engineering'
+  const teamId = any.integer()
+
+  function configure (config, { nop = true } = {}) {
+    const log = { debug: jest.fn(), error: console.error }
+    const errors = []
+    return new Teams(nop, github, { owner: org, repo: 'test' }, config, log, errors)
+  }
+
+  function mockExistingTeam (overrides = {}) {
+    github = {
+      paginate: jest.fn()
+        .mockImplementation(async (fetch, params) => {
+          if (typeof fetch !== 'function') {
+            return []
+          }
+          const response = await fetch(params)
+          return response.data
+        }),
+      rest: {
+        teams: {
+          create: jest.fn().mockResolvedValue(),
+          getByName: jest.fn(),
+          addOrUpdateRepoPermissionsInOrg: jest.fn().mockResolvedValue()
+        },
+        repos: {
+          listTeams: jest.fn().mockResolvedValue({
+            data: [
+              {
+                id: teamId,
+                slug: teamSlug,
+                name: teamDisplayName,
+                permission: 'push',
+                notification_setting: 'notifications_enabled',
+                ...overrides
+              }
+            ]
+          })
+        }
+      },
+      request: Object.assign(jest.fn().mockResolvedValue(), {
+        endpoint: jest.fn().mockReturnValue({})
+      })
+    }
+  }
+
+  it('reports no changes when only the display name differs from the slug', async () => {
+    mockExistingTeam()
+
+    const plugin = configure([
+      { name: teamSlug, permission: 'push' }
+    ])
+
+    const result = await plugin.sync()
+
+    // sync() only resolves with an array of NopCommands when compareDeep detects a change.
+    // Before the fix, the name/slug mismatch made compareDeep report the whole team as an
+    // addition + deletion even though nothing changed, so this would be a populated array.
+    if (result !== undefined) {
+      throw new Error(
+        'Expected sync() to resolve with no nop output for an unchanged team, but got:\n' +
+        JSON.stringify(result, null, 2)
+      )
+    }
+
+    expect(github.request).not.toHaveBeenCalled()
+    expect(github.rest.teams.addOrUpdateRepoPermissionsInOrg).not.toHaveBeenCalled()
+  })
+
+  it('still reports a genuine permission change without noise from the name/slug mismatch', async () => {
+    mockExistingTeam({ permission: 'pull' })
+
+    const plugin = configure([
+      { name: teamSlug, permission: 'push' }
+    ])
+
+    const result = await plugin.sync()
+
+    // result[0] is the informational summary NopCommand produced by compareDeep;
+    // result[1] is the actual PUT action produced by update().
+    const [summary] = result || []
+    const hasPhantomDiff =
+      !summary ||
+      !summary.action ||
+      JSON.stringify(summary.action.additions) !== JSON.stringify({}) ||
+      JSON.stringify(summary.action.deletions) !== JSON.stringify({})
+
+    if (hasPhantomDiff) {
+      throw new Error(
+        'Expected only a `permission` modification (no additions/deletions) for a team whose ' +
+        'permission genuinely changed, but got:\n' +
+        JSON.stringify(result, null, 2)
+      )
+    }
+
+    expect(summary.action.modifications).toEqual([
+      expect.objectContaining({ permission: 'push' })
+    ])
+  })
+})