My replacement battery (bought from Fixje in the Netherlands) had a rather thick rubber plate glued onto the top of the battery connector, which made it difficult to reattach the back cover. Specifically, the clip in the middle of the back cover could not reach into the slot.
The rubber plate could be removed which made the back close (and also made it look like the battery connector of the original battery), but the middle clip would nevertheless not attach with a clicking sound. Still, the back covers attached tightly and does not flex when pressed in the middle.
It's possible that that specific replacement battery is a hair of a millimetre thicker than the original battery which prevents the middle clip to reach into the slot fully.
