There are several, perfectly legit, possible reasons for that DNA databases are known to have a small percentage of corrupt data, specially early data. There i

There are several, perfectly legit, possible reasons for that DNA databases are known to have a small percentage of corrupt data, specially early data. There is not anything strange in modifying or deleting an item in a database. Database managers do it all the time when finding an error. Maybe those sequences were duplicated. Maybe they were wrongly translated but nobody noticed it until the covid suddenly became very popular. Maybe the publication that provided this data were bad science and retracted later. Fixing a bunch of mistakes in taxonomy that sleep for years until a specialist came and reviewed the old material is not uncommon in biology.