diff --git a/src/addon/mod/forum/pages/discussion/discussion.ts b/src/addon/mod/forum/pages/discussion/discussion.ts
index bc5b23206..c8d18d494 100644
--- a/src/addon/mod/forum/pages/discussion/discussion.ts
+++ b/src/addon/mod/forum/pages/discussion/discussion.ts
@@ -331,6 +331,8 @@ export class AddonModForumDiscussionPage implements OnDestroy {
             return this.forumProvider.getDiscussionPosts(this.discussionId, this.cmId).then((response) => {
                 onlinePosts = response.posts;
                 ratingInfo = response.ratinginfo;
+                this.courseId = response.courseid;
+                this.forumId = response.forumid;
             }).then(() => {
                 // Check if there are responses stored in offline.
                 return this.forumOffline.getDiscussionReplies(this.discussionId).then((replies) => {
@@ -371,17 +373,13 @@ export class AddonModForumDiscussionPage implements OnDestroy {
             let posts = offlineReplies.concat(onlinePosts);
 
             const startingPost = this.forumProvider.extractStartingPost(posts);
-            if (startingPost) {
-                // Update discussion data from first post.
-                this.discussion = Object.assign(this.discussion || {}, startingPost);
-            }
 
             // If sort type is nested, normal sorting is disabled and nested posts will be displayed.
             if (this.sort == 'nested') {
                 // Sort first by creation date to make format tree work.
                 this.forumProvider.sortDiscussionPosts(posts, 'ASC');
 
-                posts = this.utils.formatTree(posts, 'parent', 'id', this.discussion.id);
+                posts = this.utils.formatTree(posts, 'parent', 'id', this.discussion ? this.discussion.id : startingPost.id);
             } else {
                 // Set default reply subject.
                 const direction = this.sort == 'flat-newest' ? 'DESC' : 'ASC';
@@ -424,6 +422,10 @@ export class AddonModForumDiscussionPage implements OnDestroy {
             }).catch(() => {
                 // Ignore errors.
             }).then(() => {
+                if (startingPost) {
+                    // Update discussion data from first post.
+                    this.discussion = Object.assign(this.discussion || {}, startingPost);
+                }
 
                 if (!this.discussion) {
                     // The discussion object was not passed as parameter and there is no starting post. Should not happen.
diff --git a/src/addon/mod/forum/providers/forum.ts b/src/addon/mod/forum/providers/forum.ts
index fa6cebdfc..ff91b9935 100644
--- a/src/addon/mod/forum/providers/forum.ts
+++ b/src/addon/mod/forum/providers/forum.ts
@@ -496,7 +496,8 @@ export class AddonModForumProvider {
      * @param siteId Site ID. If not defined, current site.
      * @return Promise resolved with forum posts and rating info.
      */
-    getDiscussionPosts(discussionId: number, cmId: number, siteId?: string): Promise<{posts: any[], ratinginfo?: CoreRatingInfo}> {
+    getDiscussionPosts(discussionId: number, cmId: number, siteId?: string): Promise<{posts: any[], courseid?: number,
+            forumid?: number, ratinginfo?: CoreRatingInfo}> {
         const params = {
             discussionid: discussionId
         };