[dns-operations] C.root-servers.net experiencing trouble?

[Stephane Bortzmeyer]

>From some sites (spotted by Erwan Mas):

% dig @C.ROOT-SERVERS.NET .

; <<>> DiG 9.2.4 <<>> @C.ROOT-SERVERS.NET .
;; global options:  printcmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: SERVFAIL, id: 14262
...

The offending instance is "iad1d.c.root-servers.org".

>From other sites, it is OK ("iad1c.c.root-servers.org" or
"ord1a.c.root-servers.org").

Anyone from C-root / Cogent here?