Terminated Interactive Job Impacts Nightly Processing

I have a interactive inventory inquiry program that users run throughout
the day. This program calls many other programs to gather information about
current inventory levels (items in transit between facilities, items
backordered, etc.).

On Wednesday at 16:45, a user went into this program using his client
(iAccess for Windows), did some work, and then hit the "red X" and closed
the session (he normally doesn't do this). There were no messages of any
kind in QSYSOPR or in DSPLOG for this session.

Our nightly process runs at 21:00, that night a number of processes did not
complete due to locked files (mostly file reorgs). At 00:15 on Thursday we
see an entry in DSPLOG where the users session is finally ended due to the
QINACTITV time-out, which is set to 150 minutes. QINACTMSGQ is set to
*ENDJOB.

In addition, we have a job that runs 15 minutes before our nightly job that
kills all the jobs in QINTER. This job reported no running jobs in QINTER
Wednesday night.

At this point, It appears that this users incorrectly ended job held files
open causing the nightly process to fail.

We are running 7.1 with cummlative PTF's last applied about 3 months ago.
iAccess for Windows on the users PC (which is WIndows 7 with current fixes)
is at the latest level.

A Google search turned up some related information, but nothing directly
helpful. IBM Fix Central turned up a PTF (SI46398) that addresses QINACTITV
issues that we do not have on our system which may be part of the problem.

We are left pondering this issue. It has never happened before, to the best
of our knowledge. Why don't we see any evidence that this job was running
after the user ended it at 16:50 or so until the timeout at 00:15, some
almost 8 hours later? It doesn't appear that the QINACTITV timer worked
even though it should have trigger a number of times in the 8 hour period.

DSPLOG shows the session start at 14:17 and then end at 00:15 with nothing
else. There is a job log for the session showing various activity from
14:17 until 16:48 when they hit the X, and then nothing until the timeout
at 00:15.

The program is compiled DFTACTGRP(*NO) and ACTGRP('IN'). The called
programs are also compiled with DFTACTGRP(*NO) but some have different
activation groups.

Has anyone had a similar problem?

Thanks.