Errata are gathered - and threads do already exist for various products. Unusually HARP SF and HARP SF Xtreme have not acquired dedicated threads for this. When there are sufficient errata gathered, the master files for the pdfs (and print files) will be "opened" and the corrections made to the products. For HARP SF and HARP SF Xtreme, there may now be enough to warrant an opening. In HARP Fantasy, applying errata will be timed with HARP Bestiary as applying the monster creation processes vigorously is most likely to discover errata not spotted by fans yet.
Best wishes,
Nicholas