The 'load earlier flights' is broken for some planes.

Eg. https://www.flightradar24.com/data/aircraft/hz-ak40

When you click the button at the bottom it just adds the existing list to the bottom, ie. repeating what's already on your screen. For the record there's only a couple of days flight history for this frame prior to 3 Jan anyway but I'm pretty sure the hex was added prior to its delivery on 28 Dec as SVA9020 so the page load behaviour is not normal.