4.2.2 Update Failure: PHP has encountered a Stack overflow

I was previously able to install updates with no issue, but now receive the following error on one of my sites.

“PHP has encountered a Stack overflow”

Here is what I did to no avail:
1. Set memory_limit in PHP.INI to 512M (was not set previously)

2. Added the following 2 lines to wp-config.php (was not set previously)
define(‘WP_MEMORY_LIMIT’, ‘120M’);
define(‘WP_MAX_MEMORY_LIMIT’, ‘256M’);
(Note, I tried 64M, then 96M, and finally 120M. I even tried without the maximum memory limit setting too.)

3. I disabled all plug-ins before trying the update as well.

All actions so far yield the same.