Steps to reproduce the issue

In frontend, try to access a heavy page, with lot of resources (galleries, modules, extensions...)

Expected result

The page being normally displayed

Actual result

The server triggers an error 500.
Log entry: "PHP Fatal error: Nesting level too deep - recursive dependency? in /JOOMLA_DIRECTORY/libraries/joomla/event/dispatcher.php on line 198

System information (as much as possible)

Debian 8.10 (Jessie)
Apache 2.4.10
PHP 5.6.33-0+deb8u1
Mysql 5.5.59
Joomla! version 3.8.6

Additional comments

The problem is a recursive comparison on line 198 of file libraries/joomla/event/dispatcher.php: $check['handler'] == $observer['handler']
It's a circular reference problem, as described in: http://www.richardlord.net/blog/php/php-nesting-level-too-deep-recursive-dependency.html

Reference:
http://php.net/manual/en/language.oop5.object-comparison.php