Does not work with PHP 7+

well, I know it works perfectly on php 7.0, 7.1, 7.2 and 7.3 @dmpilotwings , it is even automatically tested with each commit on github on (amongst others) those php-versions, I have it running on 7.0 and 7.3 myself and 99% of the optimization jobs we do are done on 7.x and AO always works without any issues.

moreover AO has no occurence of split in the PHP-code, only in the 2 JS-files (both only loaded on wp-admin, one for the slider near the top right corner of the settings-screen, one for the admin notice dismissal logic).

conclusion; something else is the culprit ??

have a nice day,
frank

One thing that helps in situations like this is to read, read, and read some more. Most plugins have some sort of support forum and when looking in each one when a problem may arise you will see someone, be it a user or developer of the plugin state. ALWAYS BACK UP BEFORE INSTALLING A PLUGIN. What i do is I install WP in a sub folder then move it to the front end. Everytime I go to install a plugin I copy the files from the front end to the sub folder. I install the plugin, if it breaks the site and I can not fix it I remove the plugin and copy the files and folders from the sub folder back to the front.

Not to mention this is a plugin that is directly interacting with our JS and CSS files (NOT YOUR PHP FILES). Optimizations provided by plugins that are doing that may break features of our theme or plugins. I would say most likely the culprit was not the plugin but possibly the theme that did not want to negotiate on the style or JS being changed. For instance some themes there is a place you would like to change the color of a font, but you cant, you go into the style sheet and change it there and upon reload the theme changes it back. That is a conflict when using a plugin like this, because the plugin and the theme are fighting each other.

Simple FREE solution, always back everything up before installing and activating a plugin.