From my personal experience it is best to avoid non Netflix original anime on Netflix because of this missing episode issue your experiencing. This is because Netflix much like any other streaming service needs to get licensing to stream the episodes. In certain cases they can only have licencing for a portion of the episodes because its cheaper for them. This issue is a thing from Netflix to Crunchyroll, and everything in between. Though with Netflix original anime such as Violet evergarden are released in binge worthy totality because thats how Netflix has made its mark with everything they stream. So my advice to you is to stick to other streaming sites honestly, but if you want to ficus on Netflix look for Netflix original anime as it will be released completely since Netflix holds the licensures for it.