I found the cause. "Linkgrabber -> Group single files in various package" was unchecked, but I am not sure how it affected single file download. File size changed to 1198842923 and it has right duration.
Code:
$ ls -al MIDD-885\ 1日10回射精しても止まらないオーガズムSEX_4.mp4
-rwxrwx--- 1 root plugdev 1198842923 Dec 19 21:42 MIDD-885 1日10回射精しても止まらないオーガズムSEX_4.mp4
Thanks.