report file doesn't exist when delete in editable grid

Question

I am trying to delete a row in a editable grid by "times icon. a!localVariables(
 local!deleteDocument: tostring(loggedInUser()),
 local!a: document(34081, "folderName"),
 local!documentChildren: a!refreshVariable(folder(1685, "documentChildren")),
 local!documentChild,
 local!newFile,
 local!newFileInfo,
 local!documentInfo: 'type!{urn:com:appian:types:KONE}CSE_DOCUMENTS'(),
 local!fileId,
 local!deleteIndex:0,
 local!UserDocuments: a!refreshVariable(
 if(
 isnull(ri!tenderId),
 {},
 rule!CSE_USERDOCUMENTMATCH(
 tostring(loggedInUser()),
 tointeger(ri!tenderId)
 )
 )
 ),
 local!fileList: a!refreshVariable(
 a!forEach(
 items: local!documentChildren,
 expression: a!localVariables(
 local!documentChild: fv!item,
 a!forEach(
 items: local!UserDocuments,
 expression: if(
 document(local!documentChild, "name") = document(fv!item.documentid, "name"),
 if(
 document(local!documentChild,"id")=tointeger(fv!item.documentid),
 fv!item,{}
 ),
 {}
 )
 )
 )
 )
 ),
 local!flattenfilelist: a!flatten(local!fileList),
 a!sectionLayout(
 contents: {
 a!richTextDisplayField(
 labelPosition: "COLLAPSED",
 value: {
 a!richTextItem(
 text: {
 a!richTextIcon(icon: "FILE", caption: "Name"),
 " Edit Documents"
 },
 color: "ACCENT",
 size: "LARGE",
 style: { "PLAIN" },
 showWhen:false(),
 )
 }
 ),
 a!fileUploadField(
 label: "New File Upload",
 labelPosition: "COLLAPSED",
 target: cons!CSE_TENDER_COMMENTS_FOLDER,
 maxSelections: 25,
 value: local!newFile,
 showWhen: if(
 isnull(ri!tenderId),
 false(),
 {
 if(
 contains(
 a!forEach(
 items: rule!CSE_CSETENDER_IDOWNER(ri!tenderId),
 expression: fv!item
 ),
 tostring(loggedInUser())
 ),
 true,
 false,
 
 )
 }
 ),
 saveInto: {
 a!save(target: local!newFile, value: save!value),
 a!save(
 target: local!fileId,
 value: tointeger(local!newFile),
 
 ),
 a!save(
 target: local!documentInfo.DOCUMENT_TYPE_ID,
 value: a!forEach(items: local!fileId, expression: fv!item)
 ),
 a!save(
 target: local!documentInfo.TITLE,
 value: a!forEach(items: local!fileId, expression: " ", )
 ),
 a!save(
 target: local!documentInfo.ENTITY_ID,
 value: a!forEach(
 items: local!fileId,
 expression: ri!tenderId,
 
 )
 ),
 a!save(
 target: local!documentInfo.ACTIVE,
 value: a!forEach(items: local!fileId, expression: 1)
 ),
 a!save(
 target: local!documentInfo.CREATED_BY,
 value: a!forEach(
 items: local!fileId,
 expression: loggedInUser(),
 )
 ),
 
 },
 validations: {}
 ),
 a!buttonArrayLayout(
 buttons: {
 a!buttonWidget(
 label: "save into Folder",
 showWhen: if(
 isnull(ri!tenderId),
 false(),
 {
 if(
 contains(
 a!forEach(
 items: rule!CSE_CSETENDER_IDOWNER(ri!tenderId),
 expression: fv!item
 ),
 tostring(loggedInUser())
 ),
 true,
 false,
 
 )
 }
 ),
 saveInto: {
 a!startProcess(
 processModel: cons!CSE_ADD_CSE_DOCUMENTS,
 processParameters: {
 documentId: local!fileId,
 tenderId: ri!tenderId,
 user: tostring(loggedInUser())
 }
 ),
 },
 confirmMessage: "You sure you want to upload these files?",
 style: "PRIMARY",
 loadingIndicator:true(),
 submit:true()
 )
 },
 align: "START"
 ),
 a!columnsLayout(
 columns: {
 a!columnLayout(
 contents: {
 a!gridLayout(
 label: "Document list",
 labelPosition: "COLLAPSED",
 headerCells: {
 a!gridLayoutHeaderCell(label: "Document"),
 a!gridLayoutHeaderCell(label: "Delete")
 },
 columnConfigs: {
 a!gridLayoutColumnConfig(width: "DISTRIBUTE", weight: 2),
 a!gridLayoutColumnConfig(width: "DISTRIBUTE", weight: 1)
 },
 rows: {
 a!forEach(
 items: local!flattenfilelist,
 expression: a!gridRowLayout(
 contents: {
 a!linkField(
 labelPosition: "ABOVE",
 links: {
 a!documentDownloadLink(
 label: document((fv!item.documentid), "name"),
 document: todocument(fv!item.documentid)
 )
 }
 ),
 a!richTextDisplayField(
 value: {
 a!richTextIcon(
 icon: "times",
 link: {
 a!submitLink(
 saveInto: {
 a!startProcess(
 processModel: cons!CSE_DOCUMENT_DELELTEBYDOCUMENT,
 processParameters: {
 deleteDocument: fv!item.documentid,
 deleteid: fv!item.id,
 }
 ),
 a!save(
 target: local!documentChildren,
 value: folder(1685, "documentChildren")
 ),
 a!save(
 target: local!UserDocuments,
 value: if(
 isnull(ri!tenderId),
 {},
 rule!CSE_USERDOCUMENTMATCH(tostring(loggedInUser()), ri!tenderId),
 )
 ),
 a!save(
 target:local!flattenfilelist,
 value:remove(local!flattenfilelist, fv!index)
 ),
 /*a!save(target:local!deleteIndex,value:local!deleteIndex+1),*/
 },
 confirmMessage: "Are you sure you want to delete this file?"
 )
 },
 linkStyle: "STANDALONE",
 showWhen: if(
 isnull(ri!tenderId),
 false(),
 {
 if(
 contains(
 a!forEach(
 items: rule!CSE_CSETENDER_IDOWNER(ri!tenderId),
 expression: fv!item
 ),
 tostring(loggedInUser())
 ),
 true,
 false,
 
 )
 }
 ),
 color: "NEGATIVE",
 )
 },
 align: "CENTER",
 )
 }
 )
 )
 },
 selectionSaveInto: {},
 validations: {},
 shadeAlternateRows: true,
 )
 }
 )
 }
 )
 }
 )
) 
 If i click the first time of the times icon it is good, it delete the file and delete the row as i expected, but if i click twice it disappear, but the files is definitely exists in the folder why it report 
 " Interface Definition: Expression evaluation error at function a!forEach [line 176]: Error in a!forEach() expression during iteration 1: Expression evaluation error at function 'document' [line 184]: Document Does Not Exist or has been Deleted "?