SYS21 - Location Control Incorrect Balance Update

Standard System - v352 SP4

We are using Location Control on several of our stockrooms.

We do DRP orders to transfer stock from a non-location
controlled stockroom into a location controlled stockroom.

I have now had several instances where the location balances
in the to stockroom have been updated with two or three times
the amount of stock that was transferred. The actual stock
balance is correct it is just the location balances that
get updated incorrectly. i.e. if I transferred 6 then the
stock balance is updated by 6 but the location balance is
updated by 12 or 18.

It is not all DRP orders into this location controlled stockroom
that have this problem (dont you just love intermittent problems).

When a problem does occur I am made aware of the problem the
following day because we run the 5/INUI - Rebuild balances from
locations (in report only mode) each night.

Just wondering if somebody else has experienced something similar
and what the resolution was.

Thanks,
Gary.