diff --git a/server/objects/files/EBookFile.js b/server/objects/files/EBookFile.js
index a3558a8884..ae40dc8844 100644
--- a/server/objects/files/EBookFile.js
+++ b/server/objects/files/EBookFile.js
@@ -16,7 +16,7 @@ class EBookFile {
   construct(file) {
     this.ino = file.ino
     this.metadata = new FileMetadata(file.metadata)
-    this.ebookFormat = file.ebookFormat
+    this.ebookFormat = file.ebookFormat || this.metadata.format
     this.addedAt = file.addedAt
     this.updatedAt = file.updatedAt
   }
diff --git a/server/objects/mediaTypes/Book.js b/server/objects/mediaTypes/Book.js
index e9eec4512a..598c226502 100644
--- a/server/objects/mediaTypes/Book.js
+++ b/server/objects/mediaTypes/Book.js
@@ -73,7 +73,7 @@ class Book {
       numInvalidAudioFiles: this.invalidAudioFiles.length,
       duration: this.duration,
       size: this.size,
-      ebookFormat: this.ebookFile ? this.ebookFile.ebookFormat : null
+      ebookFormat: this.ebookFile?.ebookFormat
     }
   }
 
@@ -90,7 +90,7 @@ class Book {
       size: this.size,
       tracks: this.tracks.map(t => t.toJSON()),
       missingParts: [...this.missingParts],
-      ebookFile: this.ebookFile ? this.ebookFile.toJSON() : null
+      ebookFile: this.ebookFile?.toJSON() || null
     }
   }
 
diff --git a/server/scanner/BookScanner.js b/server/scanner/BookScanner.js
index ed905a03d8..1e51cf5262 100644
--- a/server/scanner/BookScanner.js
+++ b/server/scanner/BookScanner.js
@@ -160,6 +160,7 @@ class BookScanner {
       // Prefer to use an epub ebook then fallback to the first ebook found
       let ebookLibraryFile = libraryItemData.ebookLibraryFiles.find(lf => lf.metadata.ext.slice(1).toLowerCase() === 'epub')
       if (!ebookLibraryFile) ebookLibraryFile = libraryItemData.ebookLibraryFiles[0]
+      ebookLibraryFile = ebookLibraryFile.toJSON()
       // Ebook file is the same as library file except for additional `ebookFormat`
       ebookLibraryFile.ebookFormat = ebookLibraryFile.metadata.ext.slice(1).toLowerCase()
       media.ebookFile = ebookLibraryFile
@@ -386,6 +387,7 @@ class BookScanner {
     }
 
     if (ebookLibraryFile) {
+      ebookLibraryFile = ebookLibraryFile.toJSON()
       ebookLibraryFile.ebookFormat = ebookLibraryFile.metadata.ext.slice(1).toLowerCase()
     }
 
diff --git a/server/scanner/LibraryItemScanData.js b/server/scanner/LibraryItemScanData.js
index cae2c70ec1..7bfcdefcae 100644
--- a/server/scanner/LibraryItemScanData.js
+++ b/server/scanner/LibraryItemScanData.js
@@ -102,7 +102,7 @@ class LibraryItemScanData {
     return this.libraryFiles.filter(lf => globals.SupportedImageTypes.includes(lf.metadata.ext?.slice(1).toLowerCase() || ''))
   }
 
-  /** @type {LibraryItem.LibraryFileObject[]} */
+  /** @type {import('../objects/files/LibraryFile')[]} */
   get ebookLibraryFiles() {
     return this.libraryFiles.filter(lf => globals.SupportedEbookTypes.includes(lf.metadata.ext?.slice(1).toLowerCase() || ''))
   }