strange name when "failed to give user a random guestname"

[yugecin]

server_log.txt:

[20:51:42] [join] [FG]CorporalSun464YT has joined the server (0:xxxxxxxxx)
[20:51:58] login: failed to give user a random guestname
[20:51:59] [part] [FG]CorporalSun464YT has left the server (0:2)

irc:

[20:51:42] <@Anna^> -> [FG]CorporalSun464YT(0) connected to the server
[20:51:59] <@Anna^> <- @yqmzqgwajÆ(0) disconnected from the server (kicked)

that name is not valid (at least when using sa-mp's default name filter)

[yugecin]

Actually why did it fail to give a random guestname? The user was alone on the server.

[yugecin]

Actually why did they have a different name on IRC than in server_log.txt?