How to reproduce:
1. Download and open the project from OC
2. Notice that "amused" sprite's pivot is in the center
3. Build AssetBundle (Assets -> AssetBundles -> Build AssetBundles)
4. Open and play testScene scene
5. Both sprites stand in the same line. One in the left was in the scene, one in the right is loaded from asset bundles
6. Changes "amused" sprite's pivot (for example to Top Left)
7. Repeat 3-4 steps
8. Notice that both sprites look the same as in step 5

Reproducible: 5.3.6p5, 5.4.1p1, 5.5.0b3

By Design: The example case uses WWW.LoadFromCacheOrDownload( bundleURL, 0 ). That second parameter of '0' is the declared version of the bundle. Unity will cache that bundle on first download, and mark it as "version 0". Until someone calls LoadFromCacheOrDownload with a higher version, Unity will continue to use the cached version. This is independent of the underlying bundle changing.
Solution: The preferred method is to download the manifest which has the hash for all the bundles, then call UnityWebRequest.GetAssetBundle( bundleURL, bundleHash, 0) (this '0' is an unrelated CRC value).