It's of course a mistake and it's mainly because the Plant List use different sources that may have a different approach of taxonomy or have different level of cleaning... Here, Hepatica nobilis is an accepted name by Tropicos but the genus
Hepatica is synonym of
Anemone and this is the last 10 year position of taxonomists.
This synonymy is cautious. It cames from a molecular phylogeny from a south-african team which lump every genus closed to
Anemone (as
Pulsatilla,
Hepatica and many others) so that the
Anemone genus is monophyletic (=it gather all the species that have a common ancestor). Recent papers suggest that this wide
Anemone genus senso lato is not monophyletic and that Clematis might root in it. This would need to split the genus
Anemone senso lato. The problem is that the phylogeny doesn't match the common sub-classification of subgenus/section of Anemone... and you can't use this classical classification to make new genus and new combinaison. Obviously, two "genus" are monophyletic : Pulsatilla and Hepatica and they are quite far from each other. To restore this two genus, taxonomists have to resolve the position of the others species and other "genus" to have a taxonomy coherent with phylogeny. This needs a lot of works because Anemone s.l. is a big genus with species from all over the world...
Until this revision, use what is the best for you Anemone hepatica, Hepatica nobilis or Anemone (Hepatica) nobilis