Fasciola Hepatica and Fasciola Gigantica are two species that are not killed by Ablendazole type or Prazi based drugs, based on all the studies I've read, because their tegumental layer is too thick. If something generically says "liver flukes" that does not mean it will impact Fasciola Gigantica or Fasciola Hepatica. Unless you find a study that specifically mentiones Fasciola Gigantica or Fasciola Hepatica consider it not effective.
You can go to pubmed.gov to research it yourself and I recommend that you do. If you use the search terms "Fasciola Hepatica" and "Fasciola Gigantica" I don't think you will find any successful studies of any Albendazole type drug. I haven't found any and I have searched a lot. I find only failures. But perhaps you will find something.
I believe everyone here should using pubmed.gov as that is where all the true studies are. What you referenced is someone's loose interpretation of something they learned from goodness knows where that doesn't even identify the species of liver flukes they are referring to. If you are not reading an actual study related to a specific species, don't believe it. It is just a general statement and may or may not be true relative to a specific species.