diff --git a/services/web/app/src/Features/Project/ProjectListController.mjs b/services/web/app/src/Features/Project/ProjectListController.mjs
index cb9f6949da..53bf7c835c 100644
--- a/services/web/app/src/Features/Project/ProjectListController.mjs
+++ b/services/web/app/src/Features/Project/ProjectListController.mjs
@@ -578,21 +578,6 @@ async function projectListPage(req, res, next) {
     }
   }
 
-  let splitTestUserProperties
-  if (isSaas) {
-    try {
-      ;[splitTestUserProperties] = await Modules.promises.hooks.fire(
-        'getSplitTestUserProperties',
-        userId
-      )
-    } catch (err) {
-      logger.error(
-        { err, userId },
-        'Failed to build split test user properties for customer.io'
-      )
-    }
-  }
-
   Modules.promises.hooks
     .fire('setUserProperties', userId, {
       overleaf_id: userId,
@@ -617,7 +602,6 @@ async function projectListPage(req, res, next) {
       ...(groupRole && { group_role: groupRole }),
       is_managed_user: Boolean(user.enrollment?.managedBy),
       ...(user.email && { email: user.email }),
-      ...splitTestUserProperties,
     })
     .catch(err => {
       logger.error({ err }, 'Failed to set user properties for customer.io')
diff --git a/services/web/app/src/Features/SplitTests/SplitTestUserGetter.mjs b/services/web/app/src/Features/SplitTests/SplitTestUserGetter.mjs
index 7790d556d1..39c3d43269 100644
--- a/services/web/app/src/Features/SplitTests/SplitTestUserGetter.mjs
+++ b/services/web/app/src/Features/SplitTests/SplitTestUserGetter.mjs
@@ -45,7 +45,7 @@ function getProjection(splitTestName) {
 
 /**
  * @param id
- * @param {string} [splitTestName] test to get; omit to fetch all assignments.
+ * @param {string} splitTestName
  * @param {string} path
  * @return {Promise<SplitTestUser>}
  */
diff --git a/services/web/test/unit/src/Project/ProjectListController.test.mjs b/services/web/test/unit/src/Project/ProjectListController.test.mjs
index 780c3de46a..fcbfb7d8d1 100644
--- a/services/web/test/unit/src/Project/ProjectListController.test.mjs
+++ b/services/web/test/unit/src/Project/ProjectListController.test.mjs
@@ -568,53 +568,6 @@ describe('ProjectListController', function () {
       )
     })
 
-    it('should send packed split test assignments to customer.io', async function (ctx) {
-      ctx.Features.hasFeature.withArgs('saas').returns(true)
-      ctx.Modules.promises.hooks.fire
-        .withArgs('getSplitTestUserProperties', ctx.user._id)
-        .resolves([{ split_test_assignments: { 'test-a': 'variant-1' } }])
-      ctx.res.render = () => {}
-
-      await ctx.ProjectListController.projectListPage(ctx.req, ctx.res)
-
-      expect(ctx.Modules.promises.hooks.fire).to.have.been.calledWith(
-        'setUserProperties',
-        ctx.user._id,
-        sinon.match({
-          split_test_assignments: { 'test-a': 'variant-1' },
-        })
-      )
-    })
-
-    it('should not request split test user properties in a non-saas environment', async function (ctx) {
-      ctx.Features.hasFeature.withArgs('saas').returns(false)
-      ctx.res.render = () => {}
-
-      await ctx.ProjectListController.projectListPage(ctx.req, ctx.res)
-
-      expect(ctx.Modules.promises.hooks.fire).to.not.have.been.calledWith(
-        'getSplitTestUserProperties',
-        sinon.match.any
-      )
-    })
-
-    it('should still send other user properties when building split test assignments fails', async function (ctx) {
-      ctx.Features.hasFeature.withArgs('saas').returns(true)
-      ctx.Modules.promises.hooks.fire
-        .withArgs('getSplitTestUserProperties', ctx.user._id)
-        .rejects(new Error('boom'))
-      ctx.res.render = () => {}
-
-      await ctx.ProjectListController.projectListPage(ctx.req, ctx.res)
-
-      const call = ctx.Modules.promises.hooks.fire
-        .getCalls()
-        .find(call => call.args[0] === 'setUserProperties')
-      expect(call).to.exist
-      expect(call.args[2]).to.not.have.property('split_test_assignments')
-      expect(call.args[2]).to.have.property('overleaf_id', ctx.user._id)
-    })
-
     it('should send enterprise_commons=true when user has commons from an enterprise_commons institution', async function (ctx) {
       ctx.Features.hasFeature.withArgs('saas').returns(true)
       ctx.UserGetter.promises.getUserFullEmails.resolves([