Hello,
For some strange case whenever I try to untick this checkbox and save changes it will automatically puts the tick mark back. I tried on my development server as well and the same case. I couldn't find any odd errors on logs as well. Before the upgrade from 1.12 to 1.14 this tick mark was enabled. I had similar case before with a plugin but then what helped was removing the plugin and re-installing. On this case I can't exactly re-do this. Any suggestions?