Currently a jQuery animation (aka "forced browser repaints in rapid succession") is used for the animating of the .wb-claim-name position when scrolling down.
E.g. the "located in the administrative territorial entity" label on https://www.wikidata.org/wiki/Q70
Can by done by adding a transition declaration in the stylesheet, and updating the callback to set pure css() values instead of animate().
Also, it seems that when scrolling back up the value is not restored correctly (may be an upstream bug in jQuery UI). It ends with:
position: relative; top: 0.0117645263670028px; left: 0px;