Framed-IP-Address not inserted in mysql

[Bernd]

Hi,

running FreeRADIUS Version 3.0.4 (built for host 
x86_64-redhat-linux-gnu, built on Mar  5 2015 at 23:41:36) from stock 
packages on a CentOS 7 machine.

I have the problem that I see Framed-IP-Address entries in radacct log 
files:

Wed Dec  7 15:11:57 2016
	Acct-Session-Id = '0004xxxx'
	Framed-Protocol = PPP
	Framed-IP-Address = 10.2.3.4
	User-Name = 'user at example.com'
	Acct-Session-Time = 111
	Acct-Input-Octets = 3499
	Acct-Output-Octets = 5252
	Acct-Input-Packets = 45
	Acct-Output-Packets = 57
	Acct-Status-Type = Stop
	Service-Type = Framed-User
	Acct-Delay-Time = 0
	NAS-IP-Address = 12.13.14.15
	Event-Timestamp = 'Dec  7 2016 15:11:57 CET'
	Acct-Unique-Session-Id = '297cb70bcbc4a02b1d1xyz123'
	Timestamp = 1481119917

but they're *not* being inserted into the MySQL database (field is 
empty, tcpdump shows that clearly a '' is being transmitted to MySQL):

INSERT INTO radacct (acctsessionid,		acctuniqueid,		username, 
realm,			nasipaddress,		nasportid, 
nasporttype,		acctstarttime,		acctupdatetime, 
acctstoptime,		acctsessiontime, 	acctauthentic, 
connectinfo_start,	connectinfo_stop, 	acctinputoctets, 
acctoutputoctets,	calledstationid, 	callingstationid, 
acctterminatecause,	servicetype,		framedprotocol, framedipaddress) 
VALUES ('0004xxxx', '297cb70bcbc4a02b1d1xyz123', 'user at example.com', '', 
'12.13.14.15', '', '', FROM_UNIXTIME(1481119920), 
FROM_UNIXTIME(1481119920), NULL, '0', '', '', '', '0', '0', '', '', '', 
'Framed-User', 'PPP', '')

Help very much appreciated.

Best,

Bernd