Form drops edited record-inserts new record instead

I have a networked Access97 application that is doing
STRANGE things.

PROCESS AS DESIGNED: The user logs in and is given a form
displaying existing records that are coded (by userid) for
that user to update. From that list, the user selects a
record and continues to a second form (the first form
closes) which displays all the fields of the selected
record which should/can be edited by the user (plus a few
non-editable key fields). There is nothing tricky to how
the records are selected for display. A simple query
behind the first form selects data records using the
userID number. The second form does a simple record select
using the active record ID number on the first form.
Nothing tricky -- no modules just queries, tables, forms
and simple macros to string it all together.

The user can open/close these two forms as often as
necessary and the record will continue to show up until a
value is entered into a "completion date" field. When that
field is no longer blank, the record will no longer be
displayed for use.

PROBLEM: About 90% of the time, things work as expected.
But 10-15% of the time, somewhere between opening the
record in the second form and closing the second form, the
edited record totally disappears (as if it were never
opened, it isn't even system date stamped) and the input
information is inserted instead into a brand new record.

Users can sometimes tell when the edit record is dropped
during processing, because key fields displaying
previously entered data go blank and the displayed
recordID (autonumber) is changed.

ERROR PATTERN: NONE! It can happen as the edit record is
first opening, in the middle of editing the form, or at
the end when closing the form. It will happen on a
specific PC 2 times in a row and the third time be fine.
It has happened at multiple locations but not for all
people and not consistently for the same person/same pc.
The same record that failed can be re-selected and work
just fine the next time.

I cannot reproduce the error myself. I have tested
everything I can think of without causing the error. I can
lose changes and avoid a system date stamp if I abort my
Access sesssion, but that doesn't create/insert a new
record with my new input. It just loses everything.

I have wondered if a momentary break in the
network/communications could break the connection to the
application to just enough that the form remains on the
screen, but selected record is discarded. Input into the
empty form would/does insert a new record.

I have asked the IT Operations group to investigate if a
network/communication problem could be the culprit, but
they haven't gotten far on this.

I have never seen this happen before and am totally
stumped but am desperate to resolve it before user
confidence is damaged. Any ideas are welcomed!!! Thanks.

Karen - or