Issue to generate dynamic xml with XMLElement - sql

Question

I have a query: (show next below):
SELECT XMLElement("PetitionMarreCSV",
XMLAttributes('http://INT010.GPA.Schemas.External.GPA_AllFile' AS "xmlns"),
XMLForest(EVENT as "Event",INSERTDATE as "InsertDate",USER_ID as "USER_ID",FIRSTNAME as "FirstName",NAME as "Name",EMAIL as "Email",LANGUAGE as "Language",COUNTRY as "COUNTRY",USER_PROFILE_PIC as "USER_PROFILE_PIC",USER_PROFILE_VIDEO as "USER_PROFILE_VIDEO",OPTIN as "OPTIN",USER_WISTIA_VIDEO as "USER_WISTIA_VIDEO",USER_ACEPT as "USER_ACEPT",USER_APROVED as "USER_APROVED",STRET as "STRET",CITY as "City",POSTALCODE as "PostalCode",TELEPHONE as "Telephone",USER_INTERESTS as "USER_INTERESTS",USER_VIDEO_VIEWS as "USER_VIDEO_VIEWS",USER_SORT_ORDER as "USER_SORT_ORDER",DALING_VAN_DE_KOPKRACHT as "DALING_VAN_DE_KOPKRACHT",TOEGANG_TOT_DE_GEZONDHEIDSZORG as "TOEGANG_TOT_DE_GEZONDHEIDSZORG",RISICO_OP_EN_BLACK_OUT as "RISICO_OP_EN_BLACK_OUT",GEPLANDE_VEROUDERING as "GEPLANDE_VEROUDERING",VERHOGING_VERZEKERINGSPRIJZEN as "VERHOGING_VERZEKERINGSPRIJZEN",DURE_INTERNET as "DURE_INTERNET",TREINVERTRAGINGEN as "TREINVERTRAGINGEN",TRAGHEID_VAN_JUSTITIE as "TRAGHEID_VAN_JUSTITIE",LAGE_RENDEMENT_SPAREKENING as "LAGE_RENDEMENT_SPAREKENING",ONGEZONDE_JUNKFOD as "ONGEZONDE_JUNKFOD",MINDER_POSTKANTOREN as "MINDER_POSTKANTOREN",OPLICHTERIJ_EN_BEDROG as "OPLICHTERIJ_EN_BEDROG",VERKOPERS_AN_HUIS as "VERKOPERS_AN_HUIS",FILENAME_SOURCE as "FileName_Source")) AS "RESULT"
FROM (SELECT EVENT,INSERTDATE,USER_ID,FIRSTNAME,NAME,EMAIL,LANGUAGE,COUNTRY,USER_PROFILE_PIC,USER_PROFILE_VIDEO,OPTIN,USER_WISTIA_VIDEO,USER_ACEPT,USER_APROVED,STRET,CITY,POSTALCODE,TELEPHONE,USER_INTERESTS,USER_VIDEO_VIEWS,USER_SORT_ORDER,DALING_VAN_DE_KOPKRACHT,TOEGANG_TOT_DE_GEZONDHEIDSZORG,RISICO_OP_EN_BLACK_OUT,GEPLANDE_VEROUDERING,VERHOGING_VERZEKERINGSPRIJZEN,DURE_INTERNET,TREINVERTRAGINGEN,TRAGHEID_VAN_JUSTITIE,LAGE_RENDEMENT_SPAREKENING,ONGEZONDE_JUNKFOD,MINDER_POSTKANTOREN,OPLICHTERIJ_EN_BEDROG,VERKOPERS_AN_HUIS,FILENAME_SOURCE
FROM ops$kli.GPA22_20150130
GROUP BY EVENT,INSERTDATE,USER_ID,FIRSTNAME,NAME,EMAIL,LANGUAGE,COUNTRY,USER_PROFILE_PIC,USER_PROFILE_VIDEO,OPTIN,USER_WISTIA_VIDEO,USER_ACEPT,USER_APROVED,STRET,CITY,POSTALCODE,TELEPHONE,USER_INTERESTS,USER_VIDEO_VIEWS,USER_SORT_ORDER,DALING_VAN_DE_KOPKRACHT,TOEGANG_TOT_DE_GEZONDHEIDSZORG,RISICO_OP_EN_BLACK_OUT,GEPLANDE_VEROUDERING,VERHOGING_VERZEKERINGSPRIJZEN,DURE_INTERNET,TREINVERTRAGINGEN,TRAGHEID_VAN_JUSTITIE,LAGE_RENDEMENT_SPAREKENING,ONGEZONDE_JUNKFOD,MINDER_POSTKANTOREN,OPLICHTERIJ_EN_BEDROG,VERKOPERS_AN_HUIS,FILENAME_SOURCE)
This query create a list of CLOB value in xml format. But, by some reason that I don't know, sometimes retrieve the next error for some CLOB result instead to show the xml value:
Error: XML document must have a top level element.
The strange thing is, if I retrieve (filter the query) only with the row who has the error instead of multiples rows, the value with the error is not anymore.
SELECT XMLElement("PetitionMarreCSV",
XMLAttributes('http://INT010.GPA.Schemas.External.GPA_AllFile' AS "xmlns"),
XMLForest(EVENT as "Event",INSERTDATE as "InsertDate",USER_ID as "USER_ID",FIRSTNAME as "FirstName",NAME as "Name",EMAIL as "Email",LANGUAGE as "Language",COUNTRY as "COUNTRY",USER_PROFILE_PIC as "USER_PROFILE_PIC",USER_PROFILE_VIDEO as "USER_PROFILE_VIDEO",OPTIN as "OPTIN",USER_WISTIA_VIDEO as "USER_WISTIA_VIDEO",USER_ACEPT as "USER_ACEPT",USER_APROVED as "USER_APROVED",STRET as "STRET",CITY as "City",POSTALCODE as "PostalCode",TELEPHONE as "Telephone",USER_INTERESTS as "USER_INTERESTS",USER_VIDEO_VIEWS as "USER_VIDEO_VIEWS",USER_SORT_ORDER as "USER_SORT_ORDER",DALING_VAN_DE_KOPKRACHT as "DALING_VAN_DE_KOPKRACHT",TOEGANG_TOT_DE_GEZONDHEIDSZORG as "TOEGANG_TOT_DE_GEZONDHEIDSZORG",RISICO_OP_EN_BLACK_OUT as "RISICO_OP_EN_BLACK_OUT",GEPLANDE_VEROUDERING as "GEPLANDE_VEROUDERING",VERHOGING_VERZEKERINGSPRIJZEN as "VERHOGING_VERZEKERINGSPRIJZEN",DURE_INTERNET as "DURE_INTERNET",TREINVERTRAGINGEN as "TREINVERTRAGINGEN",TRAGHEID_VAN_JUSTITIE as "TRAGHEID_VAN_JUSTITIE",LAGE_RENDEMENT_SPAREKENING as "LAGE_RENDEMENT_SPAREKENING",ONGEZONDE_JUNKFOD as "ONGEZONDE_JUNKFOD",MINDER_POSTKANTOREN as "MINDER_POSTKANTOREN",OPLICHTERIJ_EN_BEDROG as "OPLICHTERIJ_EN_BEDROG",VERKOPERS_AN_HUIS as "VERKOPERS_AN_HUIS",FILENAME_SOURCE as "FileName_Source")) AS "RESULT"
FROM (SELECT EVENT,INSERTDATE,USER_ID,FIRSTNAME,NAME,EMAIL,LANGUAGE,COUNTRY,USER_PROFILE_PIC,USER_PROFILE_VIDEO,OPTIN,USER_WISTIA_VIDEO,USER_ACEPT,USER_APROVED,STRET,CITY,POSTALCODE,TELEPHONE,USER_INTERESTS,USER_VIDEO_VIEWS,USER_SORT_ORDER,DALING_VAN_DE_KOPKRACHT,TOEGANG_TOT_DE_GEZONDHEIDSZORG,RISICO_OP_EN_BLACK_OUT,GEPLANDE_VEROUDERING,VERHOGING_VERZEKERINGSPRIJZEN,DURE_INTERNET,TREINVERTRAGINGEN,TRAGHEID_VAN_JUSTITIE,LAGE_RENDEMENT_SPAREKENING,ONGEZONDE_JUNKFOD,MINDER_POSTKANTOREN,OPLICHTERIJ_EN_BEDROG,VERKOPERS_AN_HUIS,FILENAME_SOURCE
FROM ops$kli.GPA22_20150130
WHERE user_id = 293
GROUP BY EVENT,INSERTDATE,USER_ID,FIRSTNAME,NAME,EMAIL,LANGUAGE,COUNTRY,USER_PROFILE_PIC,USER_PROFILE_VIDEO,OPTIN,USER_WISTIA_VIDEO,USER_ACEPT,USER_APROVED,STRET,CITY,POSTALCODE,TELEPHONE,USER_INTERESTS,USER_VIDEO_VIEWS,USER_SORT_ORDER,DALING_VAN_DE_KOPKRACHT,TOEGANG_TOT_DE_GEZONDHEIDSZORG,RISICO_OP_EN_BLACK_OUT,GEPLANDE_VEROUDERING,VERHOGING_VERZEKERINGSPRIJZEN,DURE_INTERNET,TREINVERTRAGINGEN,TRAGHEID_VAN_JUSTITIE,LAGE_RENDEMENT_SPAREKENING,ONGEZONDE_JUNKFOD,MINDER_POSTKANTOREN,OPLICHTERIJ_EN_BEDROG,VERKOPERS_AN_HUIS,FILENAME_SOURCE)
Do you know if there is a problem with this function when you try to generate several CLOB columns?