Not sure if the problem is in Wordfence Security or in the HTML Editor Syntax Highlighter plugin.
Tested: HTML Editor Syntax Highlighter (v1.6.1 and 1.6.2) with Wordfence Security v5.2.6
Problem: Disables loading screens for Live Traffic and Blocked IPs in Wordfence Security.
Also posted this issue https://wordpress.org/support/topic/breaks-wordfence-security to https://wordpress.org/support/plugin/html-editor-syntax-highlighter
Wordfence Security works fine with HTML Editor Syntax Highlighter disabled.