Can not create create a page with a markdown text on the developer portal in 3scale

Issue

• Can not create create a page with a markdown text on the developer portal
• error trace similar to

[xxx*] [3scale-admin.xxx.xxx.xxx.xxx] [nn.nnn.n.n] ** [Bugsnag] No API key configured, couldn't notify
[xxx*] [3scale-admin.xxx.xxx.xxx.xxx] [nn.nnn.n.n] 
ActiveRecord::StatementInvalid (Mysql2::Error: Incorrect string value: '\xE2\x85\xA3\x0D\x0A\x0D...' for column '<column>' at row 1: UPDATE `xxx_templates` SET `draft` = '# <text containing markdown>', `updated_at` = '<date time>' WHERE `xxx_templates`.`id` = <id>):
  <path>:107:in `save'