Zabbix ver: 3.4.3
OS: Centos 7.4
DB: MySQL 5.6.32-rel78

We upgraded our Zabbix from 3.2 (conversion of the DB from 3.2 to 3.4 was successful)

I am trying to create my own custom Dashboard (we have a default one as well) [Screen 1]
but when I am adding widgets I am getting this error while trying to save my new dashboard:

Error in query [INSERT INTO widget (dashboardid,x,y,width,height,type,name,widgetid) VALUES ('5','0','0','6','5','stszbx','','6')] [Duplicate entry '6' for key 'PRIMARY']
SQL statement execution has failed "INSERT INTO widget (dashboardid,x,y,width,height,type,name,widgetid) VALUES ('5','0','0','6','5','stszbx','','6')". [Screen 2]

This error is displayed when I am trying to save in GUI console

If I will login to the DB, open the widget table and add those parameters with the next widgetid and the values in the error (VALUES ('5','0','0','6','5','stszbx','','10')". ==> [Screen 3 and screen 4] the widget is save successfully into the new dashboard then. I can edit the dashboard on the GUI and resize it, the dashboard changed are saved then [Screen 5] BUT I cannot add another widget as the same error is displayed.