Seeing similar and receiving a notification from WordPresses Site Health feature when it occurs.
It has happened when the plugin auto-updated.
[13-Jun-2019 15:51:56 UTC] PHP Fatal error: require_once(): Failed opening required ‘/wp-content/plugins/wordfence/vendor/wordfence/wf-waf/src/init.php’ (include_path=’.:/opt/cpanel/ea-php73/root/usr/share/pear’) in /wp-content/plugins/wordfence/wordfence.php on line 64
[13-Jun-2019 15:51:58 UTC] PHP Warning: require(/wp-content/plugins/wordfence/lib/../modules/login-security/wordfence-ls.php): failed to open stream: No such file or directory in /wp-content/plugins/wordfence/lib/wordfenceClass.php on line 49
[13-Jun-2019 15:51:58 UTC] PHP Fatal error: require(): Failed opening required ‘/wp-content/plugins/wordfence/lib/../modules/login-security/wordfence-ls.php’ (include_path=’.:/opt/cpanel/ea-php73/root/usr/share/pear’) in /wp-content/plugins/wordfence/lib/wordfenceClass.php on line 49
[13-Jun-2019 15:52:01 UTC] PHP Warning: require(/wp-content/plugins/wordfence/lib/../modules/login-security/wordfence-ls.php): failed to open stream: No such file or directory in /wp-content/plugins/wordfence/lib/wordfenceClass.php on line 49
[13-Jun-2019 15:52:01 UTC] PHP Fatal error: require(): Failed opening required ‘/wp-content/plugins/wordfence/lib/../modules/login-security/wordfence-ls.php’ (include_path=’.:/opt/cpanel/ea-php73/root/usr/share/pear’) in /wp-content/plugins/wordfence/lib/wordfenceClass.php on line 49
Weird that the required path goes into lib and then back up out of it, but regardless wordfence-ls.php does not exist there but wordfence-login-security.php does.
wordfence/lib/../modules/login-security/wordfence-ls.php
wordfence/vendor/wordfence/wf-waf/src/init.php does exist for me.
Could something be getting accessed during the update process before the update is complete?