Compatibility issue, this plugin causes loopback failure

I noticed problem when trying to edit php files. in wordpress > 4.9 (IIRC) wordpress checks if editing php files in theme edit causes issues. when this plugin enabled, it causes loopback failure with following error : “Unable to communicate back with site to check for fatal errors, so the PHP change was reverted” disabling this plugin works. so there is issue here interfering with wordpress loopback connection.

To reproduce the error, have the latest wordpress with this plugin enabled and try to edit and save header.php in theme file editor