diff --git a/src/main/java/org/radarbase/appserver/entity/User.java b/src/main/java/org/radarbase/appserver/entity/User.java
index f59f95a5..fc9c32f3 100644
--- a/src/main/java/org/radarbase/appserver/entity/User.java
+++ b/src/main/java/org/radarbase/appserver/entity/User.java
@@ -61,7 +61,8 @@
 @Table(
         name = "users",
         uniqueConstraints = {
-                @UniqueConstraint(columnNames = {"subject_id", "fcm_token", "project_id"})
+                @UniqueConstraint(columnNames = {"subject_id", "project_id"}),
+                @UniqueConstraint(columnNames = {"fcm_token"})
         })
 @Entity
 @Getter
diff --git a/src/main/java/org/radarbase/appserver/service/questionnaire/protocol/GithubProtocolFetcherStrategy.java b/src/main/java/org/radarbase/appserver/service/questionnaire/protocol/GithubProtocolFetcherStrategy.java
index 22777e9f..428d5d51 100644
--- a/src/main/java/org/radarbase/appserver/service/questionnaire/protocol/GithubProtocolFetcherStrategy.java
+++ b/src/main/java/org/radarbase/appserver/service/questionnaire/protocol/GithubProtocolFetcherStrategy.java
@@ -125,6 +125,7 @@ public synchronized Map<String, Protocol> fetchProtocols() {
         Map<String, Protocol> subjectProtocolMap = users.parallelStream()
                 .map(u -> this.fetchProtocolForSingleUser(u, u.getProject().getProjectId(), protocolPaths))
                 .filter(c -> c.getProtocol() != null)
+                .distinct()
                 .collect(Collectors.toMap(ProtocolCacheEntry::getId, ProtocolCacheEntry::getProtocol));
 
         log.info("Refreshed Protocols from Github");
diff --git a/src/main/resources/db/changelog/changes/00000000000002_update_schema-20240522185927_changelog.yml b/src/main/resources/db/changelog/changes/00000000000002_update_schema-20240522185927_changelog.yml
new file mode 100644
index 00000000..499e2984
--- /dev/null
+++ b/src/main/resources/db/changelog/changes/00000000000002_update_schema-20240522185927_changelog.yml
@@ -0,0 +1,16 @@
+databaseChangeLog:
+  - changeSet:
+      id: 1543511610622-8
+      author: pauline
+      changes:
+        - dropUniqueConstraint:
+            tableName: users
+            constraintName: UKmm6u3xspqfqoolkjhsvdrqefq
+  - changeSet:
+      id: 1716400827373-1
+      author: pauline
+      changes:
+        - addUniqueConstraint:
+            columnNames: subject_id, project_id
+            constraintName: UKg6m4nzwvxqpwtrbeynasdcplo
+            tableName: users