Caching mechanisms do not track the php.ini values

[PandaHugMonster]

Have made a little check of your caching mechanisms.
When you have static php.ini and working generating docs - everything works well.
After the first run of the phpdoc for an exact directory, there generating the cache for the more fast next operation under the project.
So if after this I change 'mbstring.func_overload' in php.ini and run again the cache will be damaged.
More funny that if after the failure I change back the value of 'mbstring.func_overload' on the original one - the problem won't be solved until you remove the damaged cache from the directory of the project and regenerate from the top docs.
I experimenting with:
mbstring.func_overload = 2
&
mbstring.func_overload = 0

Experimenting under x64 Arch Linux:
Linux ***** 4.3.3-2-ARCH #1 SMP PREEMPT Wed Dec 23 20:09:18 CET 2015 x86_64 GNU/Linux
phpDocumentor version 2.8.5

Hope it helps.
Best wishes

The error of Zend unserialization() method:

[PandaHugMonster]

By the way, who has faced such a problem for workaround clear the directory with the cache of the docs.
If you don't understand what is this - just remove all content from the directory output (where the docs are being generated). and the problem will be solved.