getting 'zend_mm_heap' message on composer update when including browscap.ini

Question

I want to utilize PHP's get_browser() function, so I have included browscap = extras/lite_php_browscap.ini in my php.ini file.

I am running:

PHP 7.0.15 (cli) (built: Jan 17 2017 13:44:27) ( NTS )
Copyright (c) 1997-2017 The PHP Group
Zend Engine v3.0.0, Copyright (c) 1998-2017 Zend Technologies
    with Zend OPcache v7.0.15, Copyright (c) 1999-2017, by Zend Technologies

My website still works, and get_browser() is working great... but when I go do a composer update, I am getting a big red zend_mm_heap corrupted error message.

I've tried setting opcache.fast_shutdown=0, and even turning off opcache altogether, and that doesn't fix it.

The weird thing is, I have this same setup up on my dev server, and it works fine. The only difference I can see is that I'm running PHP 7.0.18 there.

Any ideas why this is happening, and how I can try to avoid it? Thanks!