[Bro] Lot of weird log entries like DNS_RR_unknown_type

[C.L. Martinez]

Hi all,

  Over last days, I am seeing a lot of weird errors like:

#separator \x09
#set_separator	,
#empty_field	(empty)
#unset_field	-
#path	weird
#open	2015-05-04-11-04-42
#fields	ts	uid	id.orig_h	id.orig_p	id.resp_h	id.resp_p	name	addl	notice	peer
#types	time	string	addr	port	addr	port	string	string	bool	string
1430737482.215330	CYHJwf46bhQTDkaZV9	172.22.55.1	22237	172.22.55.6	53 
DNS_RR_unknown_type	-	F	bro
1430737483.223168	CIpEYq3OXvMER15dG1	172.22.55.1	58971	172.22.55.6	53 
DNS_RR_unknown_type	-	F	bro

172.22.55.1 is our internal DNS server, and recursive queries works ok. 
Then, why this type of weird logs??

Bro 2.3.2 installed under Debian 7 host (fully updated)

Thanks.