How is radius.seq file used?

[dev]

Hi all,
I'm trying to debug a custom openLDAP module I forked based on the 
pw-radius contrib module (Ubuntu 14.04 recently migrated from 12.04). 
I'm using libfreeradius-client2 (v1.1.6-7).

What seems to be happening is the ldap daemon creates the radius.seq 
file without read/write permissions by the freeradius daemon. I suspect 
this is causing slapd to segfault:

slapd[13868]: segfault at 0 ip 00007fc6f521dcd2 sp 00007fc6eeff6e38 
error 4 in libfreeradius-client.so.2.0.0[7fc6f5216000+c000]

 From what I've read, this file is only needed for Radius Accounting. 
I'm using RADIUS for authenticating One Time Passwords generated on a 
software token so would like to try disabling radius.seq to see fi the 
problem goes away.

How can I disable radius.seq?
Thanks!