In g10/keyserver.c, keyserver_spawn() sends "KEY %s BEGIN", where %s is the key
given on commandline, which can be up to 42 characters long (0x-prefixed sha
fingerprint).
In keyserver/gpgkeys_hkp.c, send_key() expects a 16 characters max keyID, and
silently rejects longer ones (any fingerprint and 0x-prefixed long keyids).
I suggest modifying keyserver_spawn() to write the real keyid (as on the INFO
lines).