With 3.2.0 and the latest 3.2.x branch I was able to reproduce the issue reported here for 3.1: https://tracker.phpbb.com/browse/PHPBB3-12100
How to reproduce: install the extension attached to the other ticket without DEBUG defined. You won't see hello world at the top of the ACP pages until you manually refresh the cache. When disabling the extension, the cache is cleared correctly. The problem occurs only when enabling the extension.
This check fails when it shouldn't: https://github.com/phpbb/phpbb/blob/release-3.2.0/phpBB/phpbb/template/twig/node/event.php#L61