List index out of bounds: 0 in execution batch - Send email

I am trying to understand what may be going on.
My code basically sends emails through a batch. However, in the executions it is giving the error "List index out of bounds: 0".
I can’t find the problem. I am checking the size of all the lists before using.

Log Error:
12:43:37:784 FATAL_ERROR System.ListException: List index out of bounds: 0

    global class PesquisaNPSSemanalBatch implements Database.Batchable<sObject>, Database.Stateful {
    final String NOME_MODELO_EMAIL = 'NPSSemestral';
    OrgWideEmailAddress owa = [SELECT Id, Address, DisplayName FROM OrgWideEmailAddress WHERE DisplayName = 'PESQUISA' LIMIT 1];
    EmailTemplate modeloEmail = [select id, name from EmailTemplate where name =: NOME_MODELO_EMAIL limit 1];

    global Database.QueryLocator start(Database.BatchableContext bc) {
        String query = 'SELECT Id, Type, ContactId, CaseNumber, ContactEmail,DataEnvioPesquisa__c,EnviaEmailContato__c, RecordTypeId' +  
                        ' FROM Case WHERE ClosedDate = LAST_N_DAYS:7 AND EnviaEmailContato__c = true AND ContactId != null AND ContactEmail != null' +
                        ' AND Status = 'Closed'';
        System.debug('Database.getQueryLocator(query)' + Database.getQueryLocator(query));
        return Database.getQueryLocator(query);
    }
    
    global void execute(Database.BatchableContext bc, List<Case> scope){
        String REC_BULK = RecordTypeMemory.getRecType('Case', 'ContingenciaBulk');
        String REC_ASS_TC = RecordTypeMemory.getRecType('Case', 'AssistenciaTecnicaCorretiva');
        String REC_PGP = RecordTypeMemory.getRecType('Case', 'FaturamentoPGPRota');
        String REC_MP = RecordTypeMemory.getRecType('Case', 'SolicitacaoMaterialProdutivo');
        String REC_MNP = RecordTypeMemory.getRecType('Case', 'SolicitacaoMaterialNaoProdutivo');
        String REC_PUB = RecordTypeMemory.getRecType('Case', 'PickUpBulk');
        String REC_FB = RecordTypeMemory.getRecType('Case', 'FaturamentoBulk');
        String REC_TNB = RecordTypeMemory.getRecType('Case', 'TrocaNotaBulk');
        String REC_CPGP = RecordTypeMemory.getRecType('Case', 'ContingenciaPGP');
        String REC_FPGPRota = RecordTypeMemory.getRecType('Case', 'FaturamentoPGPRota');
        String REC_SPGP = RecordTypeMemory.getRecType('Case', 'SuprimentosPGP');
        String REC_BALCAO = RecordTypeMemory.getRecType('Case', 'Balcao');
        String REC_AN = RecordTypeMemory.getRecType('Case', 'AtualizacaoDeNivel');
        String REC_FATU = RecordTypeMemory.getRecType('Case', 'Faturamento');
        String REC_DEVBULK = RecordTypeMemory.getRecType('Case', 'DevolucoesBulk');
        
        System.debug('scope' + scope);
        List<Case> lstCasos = new List<Case>();
        //Variavel para armazenar se o mês de envio da pesquisa é diferente deste mes
        Boolean enviarEsteMes;
        for(Case cs : scope) {
            enviarEsteMes = cs.DataEnvioPesquisa__c != null && cs.DataEnvioPesquisa__c.month() != Date.today().month();
            if((cs.DataEnvioPesquisa__c == null || enviarEsteMes) && cs.EnviaEmailContato__c){
                if(cs.RecordTypeId != REC_BULK &&
                   cs.RecordTypeId != REC_ASS_TC &&
                   cs.RecordTypeId != REC_PGP && 
                   cs.RecordTypeId != REC_MP &&
                   cs.RecordTypeId != REC_MNP &&
                   cs.RecordTypeId != REC_PUB && 
                   cs.RecordTypeId != REC_FB && 
                   cs.RecordTypeId != REC_TNB &&
                   cs.RecordTypeId != REC_CPGP &&
                   cs.RecordTypeId != REC_FPGPRota &&
                   cs.RecordTypeId != REC_SPGP &&
                   cs.RecordTypeId != REC_BALCAO &&
                   cs.RecordTypeId != REC_AN &&
                   cs.RecordTypeId != REC_FATU &&
                   cs.RecordTypeId != REC_DEVBULK &&
                   cs.Type != 'Contato Interno' && cs.Type != 'Lead' && cs.Type != 'SPAM'){
                       lstCasos.add(cs);
                   }
            }
        }
        if(lstCasos.size() > 0){
            sendEmailNotification(lstCasos);            
        }
        
    }
    
        
    
    global void finish(Database.BatchableContext bc){}  
    
    public void sendEmailNotification(List<Case> lstCasos){
        System.debug('sendEmailNotification');   
        System.debug('lstCasos ---> ' + lstCasos.size());  
        List < Messaging.SingleEmailMessage > emails = new List < Messaging.SingleEmailMessage > ();
        List<Case> casesToUpd = new List<Case>();
        if(modeloEmail != null && modeloEmail.id != null){
           System.debug('modeloEmail.id' + modeloEmail.id);   

            for(Case c : lstCasos){
                if(c.ContactId != null){
                   System.debug('c.ContactId' + c.ContactId );   

                    Messaging.SingleEmailMessage email = new Messaging.SingleEmailMessage();
                    
                    email.setOrgWideEmailAddressId(owa.id);
                    email.setTemplateId(modeloEmail.id);
                    email.setTargetObjectId(c.ContactId);
                    email.setWhatId(c.id);
                    email.setSaveAsActivity(true);
                    emails.add(email);
                    casesToUpd.add(c);
                }
            }
        }
        
     //   Messaging.sendEmail(emails);
        
     //   Messaging.SingleEmailMessage[] messages =   new List<Messaging.SingleEmailMessage> {email};
        Messaging.SendEmailResult[] results = Messaging.sendEmail(emails, false);
        System.debug('results.size()' + results.size()); 
        if(results.size() > 0){
            
            for(Messaging.SendEmailResult r : results){
                if (r.success) {
                      
                    System.debug('The email was sent successfully.');
                    for(Case cs : casesToUpd){
                        cs.DataEnvioPesquisa__c = System.now();
                    }
                    
                    BatchLogs__c b = new BatchLogs__c();
                    b.Status__c = 'Êxito';
                    b.Name = 'NPS Semanal';
                    
                    insert b; 
                    System.debug('insert b');
                } else {
                    System.debug('The email failed to send: ' + results[0].errors[0].message);
                    BatchLogs__c b = new BatchLogs__c();
                    b.MensagemErroCompleta__c = results[0].errors[0].message;
                    b.Status__c = 'Falha';
                    b.Name = 'NPS Semanal';
                    insert b;
                    System.debug('insert b');
                    System.debug('The email failed to send: ' + results[0].errors[0].message);
                    //l.DescricaoErroNotificacaoLead__c = results[0].errors[0].message;
                }
            }
            update casesToUpd;
        }

    }
}

//System.debug('The email failed to send: ' + results[0].errors[0].message);
System.debug('The email failed to send: ' + r.errors[0].message);