fresh install.
edit a host, mark "use extended profile"
at the top, warning is displayed ;
Warning. Field [ext_host_profiles] is mandatory

at the bottom, errors are displayed (maybe those should be displayed at the top as well ?) :

Undefined index: device_alias[/srv/www/htdocs/zabbix/include/forms.inc.php:4835]
Undefined index: device_type[/srv/www/htdocs/zabbix/include/forms.inc.php:4836]
Undefined index: device_chassis[/srv/www/htdocs/zabbix/include/forms.inc.php:4837]
Undefined index: device_os[/srv/www/htdocs/zabbix/include/forms.inc.php:4838]
Undefined index: device_os_short[/srv/www/htdocs/zabbix/include/forms.inc.php:4839]
Undefined index: device_hw_arch[/srv/www/htdocs/zabbix/include/forms.inc.php:4840]
Undefined index: device_serial[/srv/www/htdocs/zabbix/include/forms.inc.php:4841]
Undefined index: device_model[/srv/www/htdocs/zabbix/include/forms.inc.php:4842]
Undefined index: device_tag[/srv/www/htdocs/zabbix/include/forms.inc.php:4843]
Undefined index: device_vendor[/srv/www/htdocs/zabbix/include/forms.inc.php:4844]
Undefined index: device_contract[/srv/www/htdocs/zabbix/include/forms.inc.php:4845]
Undefined index: device_who[/srv/www/htdocs/zabbix/include/forms.inc.php:4846]
Undefined index: device_status[/srv/www/htdocs/zabbix/include/forms.inc.php:4847]
Undefined index: device_app_01[/srv/www/htdocs/zabbix/include/forms.inc.php:4848]
Undefined index: device_app_02[/srv/www/htdocs/zabbix/include/forms.inc.php:4849]
Undefined index: device_app_03[/srv/www/htdocs/zabbix/include/forms.inc.php:4850]
Undefined index: device_app_04[/srv/www/htdocs/zabbix/include/forms.inc.php:4851]
Undefined index: device_app_05[/srv/www/htdocs/zabbix/include/forms.inc.php:4852]
Undefined index: device_url_1[/srv/www/htdocs/zabbix/include/forms.inc.php:4853]
Undefined index: device_url_2[/srv/www/htdocs/zabbix/include/forms.inc.php:4854]
Undefined index: device_url_3[/srv/www/htdocs/zabbix/include/forms.inc.php:4855]
Undefined index: device_networks[/srv/www/htdocs/zabbix/include/forms.inc.php:4857]
Undefined index: device_notes[/srv/www/htdocs/zabbix/include/forms.inc.php:4858]
Undefined index: device_hardware[/srv/www/htdocs/zabbix/include/forms.inc.php:4859]
Undefined index: device_software[/srv/www/htdocs/zabbix/include/forms.inc.php:4860]
Undefined index: ip_subnet_mask[/srv/www/htdocs/zabbix/include/forms.inc.php:4862]
Undefined index: ip_router[/srv/www/htdocs/zabbix/include/forms.inc.php:4863]
Undefined index: ip_macaddress[/srv/www/htdocs/zabbix/include/forms.inc.php:4864]
Undefined index: oob_ip[/srv/www/htdocs/zabbix/include/forms.inc.php:4865]
Undefined index: oob_subnet_mask[/srv/www/htdocs/zabbix/include/forms.inc.php:4866]
Undefined index: oob_router[/srv/www/htdocs/zabbix/include/forms.inc.php:4867]
Undefined index: date_hw_buy[/srv/www/htdocs/zabbix/include/forms.inc.php:4869]
Undefined index: date_hw_install[/srv/www/htdocs/zabbix/include/forms.inc.php:4870]
Undefined index: date_hw_expiry[/srv/www/htdocs/zabbix/include/forms.inc.php:4871]
Undefined index: date_hw_decomm[/srv/www/htdocs/zabbix/include/forms.inc.php:4872]
Undefined index: site_street_1[/srv/www/htdocs/zabbix/include/forms.inc.php:4874]
Undefined index: site_street_2[/srv/www/htdocs/zabbix/include/forms.inc.php:4875]
Undefined index: site_street_3[/srv/www/htdocs/zabbix/include/forms.inc.php:4876]
Undefined index: site_city[/srv/www/htdocs/zabbix/include/forms.inc.php:4877]
Undefined index: site_state[/srv/www/htdocs/zabbix/include/forms.inc.php:4878]
Undefined index: site_country[/srv/www/htdocs/zabbix/include/forms.inc.php:4879]
Undefined index: site_zip[/srv/www/htdocs/zabbix/include/forms.inc.php:4880]
Undefined index: site_rack[/srv/www/htdocs/zabbix/include/forms.inc.php:4881]
Undefined index: site_notes[/srv/www/htdocs/zabbix/include/forms.inc.php:4882]
Undefined index: poc_1_name[/srv/www/htdocs/zabbix/include/forms.inc.php:4884]
Undefined index: poc_1_email[/srv/www/htdocs/zabbix/include/forms.inc.php:4885]
Undefined index: poc_1_phone_1[/srv/www/htdocs/zabbix/include/forms.inc.php:4886]
Undefined index: poc_1_phone_2[/srv/www/htdocs/zabbix/include/forms.inc.php:4887]
Undefined index: poc_1_cell[/srv/www/htdocs/zabbix/include/forms.inc.php:4888]
Undefined index: poc_1_screen[/srv/www/htdocs/zabbix/include/forms.inc.php:4889]
Undefined index: poc_1_notes[/srv/www/htdocs/zabbix/include/forms.inc.php:4890]
Undefined index: poc_2_name[/srv/www/htdocs/zabbix/include/forms.inc.php:4892]
Undefined index: poc_2_email[/srv/www/htdocs/zabbix/include/forms.inc.php:4893]
Undefined index: poc_2_phone_1[/srv/www/htdocs/zabbix/include/forms.inc.php:4894]
Undefined index: poc_2_phone_2[/srv/www/htdocs/zabbix/include/forms.inc.php:4895]
Undefined index: poc_2_cell[/srv/www/htdocs/zabbix/include/forms.inc.php:4896]
Undefined index: poc_2_screen[/srv/www/htdocs/zabbix/include/forms.inc.php:4897]
Undefined index: poc_2_notes[/srv/www/htdocs/zabbix/include/forms.inc.php:4898]