Can you please provide me with a method on how this can be reproduced? Just stating a Windows version is not useful.

I think I have used Step Over over this line:
if ((!$this->data || !array_key_exists('usedAmountBase_CZK', $this->data)) && !array_key_exists('usedAmountBase_CZK', $data)) {

$this->data was null, $data was an array.

I just released Xdebug 2.4.0RC3, which hopefully addresses stability issues on Windows: http://xdebug.org/#2015_12_12 — Can you please try that? Make also sure you run this with PHP 7.0.0 (or later), and not a PHP 7 Release Candidate.

In case it does not solve the problem, please provide a full but short reproducible test case that I can run myself. That includes hopefully a single script, and an accompanying remote debugging log (which you can make by setting xdebug.remote_log=c:\windows\temp\xdebug.log in php.ini).

I can't reproduce this, and the requested feedback was not provided. I am closing this, but feel free to reopen if you can provide the requested information and the problem still occurs with Xdebug 2.4.0RC4.