when I'm working on invoice manager with Joomla 3.5.1 (might have been issue on previous versions too I'm not sure coz haven't used it in a while...) then randomly I seem to get an error message like this one:

{"notifications":[{"message":"Quote Saved!","type":"message"}],"content":{"id":"7","created_by":"833","user_id":4,"added":"2016-04-21 16:09:40","to_name":"Test","to_address":"","invoice_num":"2016-3","real_invoice_num":"3","from_name":"VIP Rehearsals Dublin","from_address":"5 Lombard Street East\r\nDublin, D2\r\nIreland","from_num":"","invoice_date":"2016-04-21 00:00:00","publish":1,"notes":"","template_id":"6","taxes":"","start_publish":"0000-00-00 00:00:00","end_publish":"0000-00-00 00:00:00","currency_before":"\u20ac","currency_after":"","status":"","to_email":"","to_company":"","from_phone":"00353 87966 8333","from_url":"www.VIPrehearsalsDublin.com","from_email":"viprehearsals@gmail.com","discount":"0.0000","invoice_duedate":"0000-00-00 00:00:00","admin_notes":"","to_city":"","to_state":"","to_country":"","to_vatid":"","to_zipcode":"","rec_year":"0","rec_month":"0","rec_day":"0","rec_nextdate":"0000-00-00","is_recurrent":0,"to_phone":"","external_type":"","external_id":"0","external_ref":"","type":"2","rec_email":"0","auth_code":"eB9IDi3TpN3jnT6Bp5n13byjvCe4GIpr8Ao0kJW6tQPNabJvyAsEMGcmLFnevPoN","computed_status":"paid","computed_total":"0.0000","language":"en-GB","last_sent":"0000-00-00 00:00:00","username":"No","contact_name":"Test","joomla_user_id":"0","subtotal":0,"display_taxes":[],"total":0,"total_paid":null,"paid_payments":0,"total_unpaid":null,"unpaid_payments":0,"total_unpaid_ontime":null,"unpaid_payments_ontime":0,"unpaid_payments_notontime":0,"formatted_date":"21 Apr 2016","formatted_total":"\u20ac0.00","formatted_subtotal":"\u20ac0.00","formatted_total_paid":"\u20ac0.00","payment_class":" ontime","rec_tooltip":"Next recurrency: 30 November -0001","allow_edit":1,"is_quote":1,"edit_link":"\/administrator\/index.php?option=com_invoices&controller=quote&tmpl=component&task=edit&cid[]=7&layout=form&modal=1","link":"\/administrator\/index.php?option=com_invoices&controller=invoice&view=invoice&cid[]=7&tmpl=component","link_contact":"\/administrator\/index.php?option=com_invoices&controller=contact&task=edit&cid[]=4","link_payments":"\/administrator\/index.php?option=com_invoices&controller=payments&invoice_id=7","link_new_payment":"\/administrator\/index.php?option=com_invoices&controller=payment&task=edit&cid[]=0&invoice_id=7&from=invoices","pdf_link":"\/administrator\/index.php?option=com_invoices&view=invoice&format=dompdf&cid[]=7","email_link":"\/administrator\/index.php?option=com_invoices&controller=invoice&task=send_email&cid[]=7&ajax=1","status_class":"default","last_sent_formatted":"Not sent","sent":0}}


Would you be able to elaborate as to what is happening with it?

Kind regards, kyle.