Incorrect DLR mapping in kannel 1.5.0

Dear Kannel users,


We have a problem with incorrect delivery reports mapping in kannel 1.5.0.
Problem is not constant and it usually occurs when there is increased
number of AO-MT SMSes sent from various senders (originating addresses)
that are requesting DLRs.



I have managed to reproduce the problem with following test. In the busy
hour (period when there is increased number of SMSes requesting DLR from
kannel) I have sent 4 SMSes (requesting DLR) to detached mobile subscriber.
Surprisingly (within several minutes) dlr-url that I have set in messages
towards detached subscriber was called 4 times, although SMSes were still
waiting to be delivered on the SMSC. I have analyzed SMPP communication
between SMS gateway (kannel) and SMSC for the period when test was
conducted and SMSC does everything correctly.



We are using kannel 1.5.0 svn version from 25.07.2012 and mysql 5.0.95 for
external dlr storage.



Please advise what might be causing this irregular behavior.



Looking forward to your answer,

Tanja