Error when highlighting code using backquotes

Entering the following into the wordpress editor:

if (true)
{
    dosomething(1);
}

Results in:

[crayon-530bc194ab4aa032760903  ]if (true)
{
    dosomething(1);
}
[/crayon]

where the [/crayon] tags are visible.

May this be a CSS styling problem?

Regards,
Marc

https://ww.wp.xz.cn/plugins/crayon-syntax-highlighter/