Unexpected SQLSTATE returned from embedded SQL

I have the following SQL that has been working as expected for about 2 years:

SELECT COALESCE(om8.suptyp,' ')
INTO :wk_OutAsnSts
FROM om01 om1
LEFT JOIN om08 om8
ON om8.outnum = om1.outnum
AND om8.suptyp = 'AS'
AND om8.recsta = '5'
WHERE om1.outnum = :wk_OutNum

The query is intended to return the EDI 856 ASN status of the "Sales Outlet" specified by "wk_OutNum".

This week we received a problem report from one of our seven warehouse locations that six outlets did
not receive the expected ASN pallet labels and Document.

This happened on Monday and Tuesday of this week at that one location, but has yet to be reported by
any other warehouse location. We send 70-90 ASN documents daily.

All location data is processed by one RPGLE program which has the SQL shown above.

I reviewed all status reports created by this program yesterday and found six examples where the
program reported SQL State = 02000 (no rows)for an outlet that >IS< defined.

Late yesterday, we identified this problem in time to repeat the procedure that runs the query,
and then successfully created and transmitted the required ASN documents.

Repeating the query now also returns the expected "row found" condition.

My question is what, other than an actual "no row" could cause SQL State = 02000 ?

Because I often see CPU well above 100%, I suspect that some kind of "time-out" may cause this ?