mismatched character '<EOF>' expecting '''

I created a batch to find duplicate leads by email or phone or mobile phone.

The batch everytime finish with success, every single batch is processed. If I have in total 10 batches to processed, my success is 10. But I receive one failure too, with the message First error: line 1:220 mismatched character '<EOF>' expecting '''.

I already review my code but without success I was able to find what is causing this message.

I have a feeling that is have to do with emails like this email'email@gmail.com, but I used the escapeSingleQuotes to prevent injection.

My code is below.

Thank you 

global class FZ_BatchDuplicateLeads Implements Database.batchable<sobject>{ 
    global Database.QueryLocator start(Database.BatchableContext BC){
        return Database.getQueryLocator('SELECT Id, FZ_ClientCode__c, FZ_SiteId__c, FZ_ClientEmail__c, FZ_MobilePhone__c, Phone FROM Account WHERE (RecordType.DeveloperName  = \'FZ_PublicClient\' OR RecordType.DeveloperName  = \'FZ_ProfessionalClient\') AND (FZ_ClientEmail__c != null OR FZ_MobilePhone__c != null OR Phone != null) ');
    }
    global void execute(Database.BatchableContext BC, List<Account> allAccounts){
        for(Account account : allAccounts){
            String whereFilter = '';
            if(String.isNotBlank(account.FZ_ClientEmail__c)){
            	whereFilter += ' FZ_ClientEmail__c = \'' + String.escapeSingleQuotes(account.FZ_ClientEmail__c) + '\'';              
            }
            if(String.isNotBlank(account.FZ_MobilePhone__c )){
                if(whereFilter != ''){
                    whereFilter += ' OR ';
                }
                whereFilter += ' FZ_MobilePhone__c = \'' + account.FZ_MobilePhone__c + '\'';
            }
            if(String.isNotBlank(account.Phone)){
                if(whereFilter != ''){
                    whereFilter += ' OR ';
                }
                whereFilter += ' Phone = \'' + account.Phone + '\'';
            }
            String query = 'SELECT Id, FZ_ClientCode__c, FZ_SiteId__c, FZ_ClientEmail__c, FZ_MobilePhone__c, Phone ' +
                            + ' FROM Account ' +
                            + ' WHERE RecordType.DeveloperName  = \'FZ_Lead\' ' +
                            + ' AND ( ' + whereFilter + ' ) ';
            List<Account> leads = Database.query(query);
            if(leads.size() > 0 && leads != null){
                System.debug('account  ' + account);
                FZ_DuplicateLeads.dealWithDuplicateLeads(leads, account);
            }
        }
    }
    global void finish(Database.BatchableContext BC){
    }
}