gpg --recv-key rejects a key

[Ineiev]

Hello,

$ gpg --version
gpg (GnuPG) 1.4.18
(&c.)

$ gpg --recv-key 0x3DBDDC68
gpg: requesting key 3DBDDC68 from hkp server keys.gnupg.net
gpg: key 35853032: rejected by import filter
gpg: Total number processed: 1

When I get the key from keys.gnupg.net using a web browser,

$ gpg --import 3DBDDC68 .key
gpg: key 35853032: public key "Brendan Cully <brendan at cs.ubc.ca>" imported
gpg: Total number processed: 1
gpg:               imported: 1
gpg: no ultimately trusted keys found

I wonder why the behavior may differ?