Undefined offset in class loader for classes without vendor namespace
If a class file from a third-party package is loaded which does not follow the
Vendor\Product\Classname convention (e.g.
Product\Classname), the class loader still tries to access the third component of the class name, leading to a warning (and thus an exception, depending on your configuration).
To fix this problem, the class loader should check in advance if it can possibly load this class (or rather if the classname conforms to the specification for the CMS universe).