ssl_ciphers directive is duplicate after 'http2_pref' enable

After entering command '/usr/local/psa/bin/http2_pref enable' it simply says:

ERR [panel] Apache config (14609715970.61978300) generation failed: Template_Exception: nginx: [emerg] "ssl_ciphers" directive is duplicate in /etc/nginx/conf.d/ssl.conf:1
nginx: configuration file /etc/nginx/nginx.conf test failed

file: /usr/local/psa/admin/plib/Template/Writer/Webserver/Abstract.php
line: 75
code: 0
nginx: [emerg] "ssl_ciphers" directive is duplicate in /etc/nginx/conf.d/ssl.conf:1
nginx:...

ssl_ciphers directive is duplicate after 'http2_pref' enable