I just downloaded the latest version of the app (276.2) and the issue is still present. If the file downloaded has no extension it does not appear in the all files view.
File downloaded was in mkv format but I tested the same behaviour with mp4
When I download the file: Name : Gotham S02E07.mp4 URL : https://leto48g.storage.yandex.net/rdisk/9275ed54d3277ad791ab49a439f21dec0b945188b1c7016b20b81bca0aba934e/565326e4/l-PiS8ql3QqpBzLH-KBG16LQoT7prebP5byT8Yr9oKA7sK4Gfe1wKNxMVU5pquIixdBjTH3FeYcXwcDuIUevzA==?uid=0&filename=Gotham%20S02E07.mp4&...