diff --git a/test/api/v3/integration/challenges/GET-challenges_challengeId_export_csv.test.js b/test/api/v3/integration/challenges/GET-challenges_challengeId_export_csv.test.js
index d82bc498ad..a683513180 100644
--- a/test/api/v3/integration/challenges/GET-challenges_challengeId_export_csv.test.js
+++ b/test/api/v3/integration/challenges/GET-challenges_challengeId_export_csv.test.js
@@ -60,9 +60,9 @@ describe('GET /challenges/:challengeId/export/csv', () => {
   });
 
   it('should return a valid CSV file with export data', async () => {
-    let res = await members[0].get(`/challenges/${challenge._id}/export/csv`);
-    let sortedMembers = _.sortBy([members[0], members[1], members[2], groupLeader], '_id');
-    let splitRes = res.split('\n');
+    const res = await members[0].get(`/challenges/${challenge._id}/export/csv`);
+    const sortedMembers = _.sortBy([members[0], members[1], members[2], groupLeader], '_id');
+    const splitRes = res.split('\n');
 
     expect(splitRes[0]).to.equal('UUID,name,Task,Value,Notes,Streak,Task,Value,Notes,Streak');
     expect(splitRes[1]).to.equal(`${sortedMembers[0]._id},${sortedMembers[0].profile.name},habit:Task 1,0,,0,todo:Task 2,0,,0`);
@@ -71,4 +71,16 @@ describe('GET /challenges/:challengeId/export/csv', () => {
     expect(splitRes[4]).to.equal(`${sortedMembers[3]._id},${sortedMembers[3].profile.name},habit:Task 1,0,,0,todo:Task 2,0,,0`);
     expect(splitRes[5]).to.equal('');
   });
+
+  it('should successfully return when it contains erroneous residue user data', async () => {
+    await members[0].update({challenges: []});
+    const res = await members[1].get(`/challenges/${challenge._id}/export/csv`);
+    const sortedMembers = _.sortBy([members[1], members[2], groupLeader], '_id');
+    const splitRes = res.split('\n');
+    expect(splitRes[0]).to.equal('UUID,name,Task,Value,Notes,Streak,Task,Value,Notes,Streak');
+    expect(splitRes[1]).to.equal(`${sortedMembers[0]._id},${sortedMembers[0].profile.name},habit:Task 1,0,,0,todo:Task 2,0,,0`);
+    expect(splitRes[2]).to.equal(`${sortedMembers[1]._id},${sortedMembers[1].profile.name},habit:Task 1,0,,0,todo:Task 2,0,,0`);
+    expect(splitRes[3]).to.equal(`${sortedMembers[2]._id},${sortedMembers[2].profile.name},habit:Task 1,0,,0,todo:Task 2,0,,0`);
+    expect(splitRes[4]).to.equal('');
+  });
 });
diff --git a/website/server/controllers/api-v3/challenges.js b/website/server/controllers/api-v3/challenges.js
index 0d6d2a4e50..8beca520f4 100644
--- a/website/server/controllers/api-v3/challenges.js
+++ b/website/server/controllers/api-v3/challenges.js
@@ -579,6 +579,16 @@ api.exportChallengeCsv = {
     let lastUserId;
     let index = -1;
     tasks.forEach(task => {
+      /**
+       * Occasional error does not unlink a user's challenge tasks from that challenge's data
+       * after the user leaves that challenge, which previously caused a failure when exporting
+       * to a CSV. The following if statement makes sure that the task's attached user still
+       * belongs to the challenge.
+       * See more at https://github.com/HabitRPG/habitica/issues/8350
+       */
+      if (!resArray.map(line => line[0]).includes(task.userId)) {
+        return;
+      }
       while (task.userId !== lastUserId) {
         index++;
         lastUserId = resArray[index][0]; // resArray[index][0] is an user id