Result set different from query than from stored procedure in Oracle - oracle

Question

I have a sp that is giving me wrong results. That sp returns a cursor which is missing some rows. Now
When we fire the query within the sp directly in a query window, correct results come up. The only difference in this query is that instead of a cursor, the query directly outputs the result set; i.e. no cursor is opened when we fire the query directly.
When we recompile the sp, correct results come up for some time, and then it is back to missing rows after some time.
Have not been able to make much progress on this. Any pointers on what to look for, how to make progress etc. are much appreciated. I can paste the sp in here if needed, and probably the sp can be rewritten in some other way to make the problem go away, but I am more interested in knowing root cause - what could be causing this strange problem?
SP
CREATE OR REPLACE PROCEDURE "SP_GETTAXSETTINGCHANNELINFO" (v_bid varchar2,
p_rdTaxSetting out SYS_REFCURSOR) as
vT_bid varchar2(100);
begin
vT_bid := v_bid;
Open p_rdTaxSetting for
Select taxmappingid, CHANNELNAME,PROPERTYNAME, PROPERTYID, TAXTYPE, ISPARTIALLYINCLUSIVE, PARTIALLYINCLUSIVEVALUE
FROM (
WITH ChannelData AS (
SELECT ONDEMAND_SELECTED_SOURCES AS OnDemandChannels,
SCHEDULED_SELECTED_SOURCES AS ScheduledChannels
FROM SUB_ORDER S
INNER JOIN CONTACT C ON S.Supplier_ID = C.Contact_ID
WHERE C.BID = vT_bid
AND S.STATUS='Complete' and current_ind = 1
),
Property_Data As (
SELECT
SC.PROPERTY_NUM AS PropertyID
,SC.Company_Name as PropertyName
,SC.competitor_number as PropertyOrder
FROM SUB_ORDER S
INNER JOIN CONTACT C ON S.Supplier_ID = C.Contact_ID
INNER JOIN SUB_ORDER_COMPETITOR SC ON S.Order_Id = SC.Order_ID
WHERE C.BID = vT_bid
AND S.STATUS='Complete' and current_ind = 1
),
ODChannel as (
select regexp_substr (OnDemandChannels, '[^,]+', 1, rn) as Channel
from (Select OnDemandChannels From ChannelData)
cross join
(select rownum rn
from (select max (length (regexp_replace (OnDemandChannels, '[^,]+'))) + 1 max_value
from (Select OnDemandChannels From ChannelData))
connect by level <= max_value)
where regexp_substr (OnDemandChannels, '[^,]+', 1, rn) is not null
),
SCDChannel As (
select regexp_substr (ScheduledChannels, '[^,]+', 1, rn) as Channel
from (Select ScheduledChannels From ChannelData)
cross join
(select rownum rn
from (select max (length (regexp_replace (ScheduledChannels, '[^,]+'))) + 1 max_value
from (Select ScheduledChannels From ChannelData))
connect by level <= max_value)
where regexp_substr (ScheduledChannels, '[^,]+', 1, rn) is not null
),
ChaData1 As (
Select
CASE lower(Channel)
WHEN 'galileo' then 'GDS'
else Channel
end AS Channel
from ODChannel
),
ChaData2 As (
Select CASE lower(Channel)
WHEN 'galileo' then 'GDS'
else Channel
end AS Channel FROM SCDChannel
),
PropData As (
Select Distinct PropertyID,PropertyName from Property_Data
order by PropertyID
),
AllChannel AS (
Select Channel From ChaData1
union
Select Channel From ChaData2
),
Prop_Cha_Data As (
Select Distinct Channel,PropertyID,PropertyName from AllChannel,Property_Data
order by Channel,PropertyID
),
Tax_Channel_Prop_Exists AS ( select
CASE lower(CHANNELNAME)
WHEN 'galileo' then 'GDS'
else CHANNELNAME
end AS CHANNELNAME,
PropertyName As PROPERTYNAME, TCP.PROPERTYID As PROPERTYID,TAXTYPE,
ISPARTIALLYINCLUSIVE, PARTIALLYINCLUSIVEVALUE,taxmappingid
from TAXSETTING_CHANNEL_PROPERTY TCP
INNER JOIN AllChannel PC On TRIM (CASE lower(TCP.CHANNELNAME)
WHEN 'galileo' then 'GDS'else TCP.CHANNELNAME end) = TRIM(PC.Channel)
INNER JOIN PropData CP On TCP.PROPERTYID = CP.PropertyID
where TCP.BID=vT_bid
)
Select Distinct taxmappingid, CHANNELNAME,PROPERTYNAME, PROPERTYID, TAXTYPE, ISPARTIALLYINCLUSIVE, PARTIALLYINCLUSIVEVALUE from Tax_Channel_Prop_Exists
UNION ALL
select DISTINCT 0 As taxmappingid, PCD.Channel As CHANNELNAME,
PCD.PropertyName As PROPERTYNAME ,
PCD.propertyid As PROPERTYID,
-1 As TAXTYPE,
0 As ISPARTIALLYINCLUSIVE,
'' As PARTIALLYINCLUSIVEVALUE
FROM Prop_Cha_Data PCD
WHERE NOT EXISTS (
Select taxmappingid FROM Tax_Channel_Prop_Exists E
WHERE E.channelname = PCD.Channel AND
E.propertyid = PCD.propertyid )
)
Order by PROPERTYNAME,CHANNELNAME ;
end SP_GetTaxSettingChannelInfo;