I'm not sure I see the problem. If the class satisfies both interfaces, why should there be an error?

E.g., consider:

    interface Iterator {
        function current();
        function key();
        function next();
        function valid();
    }

    interface RewindableIterator extends Iterator {
        function rewind();
    }

    interface ReversableIterator extends Iterator {
        function prev();
    }

    class Foo implements RewindableIterator, ReversableIterator {
        // ...
    }

Why shouldn't the class be able to implement both, as long as the method declarations don't disagree?

Your example is ok and should work correctly as both interfaces extend the same base interface and add different methods. In my given example AInterface and BInterface do not extend from a common interface. So the class which implements RewindableIterator, ReversableIterator must implement

from Iterator:
function current();
function key();
function next();
function valid();

from RewindableIterator:
function rewind();

from ReversableIterator:
function prev();

So lets change my example to:
interface AInterface {
    /** @return Aclass[] */
    public function getObjects();
}
interface BInterface {
    /** @return Bclass[] */
    public function getObjects();
}

class CClass implements AInterface, BInterface
{
    public function getObjects() {
       return ???;
    }
}
class AClass {
    public function foo() { echo "foo";}
}
class BClass {
    public function bar() { echo "bar";}
}

The certification guide states that a object can't implement two interfaces that 
share the same method, but the code still runs ok.

So if classes are going to be allowed two implement two interfaces that share the 
same method, I think that the certification exam should be changed to reflect 
this change.

Any news about it?

I think the current behavior is ok(implementing two interfaces with same signatures should be possible), but it should be documented. 

Right now the documentation states clearly: "A class cannot implement two interfaces that share function names, since it would cause ambiguity.", so it looks like an undocumented feature(bug?) with uncertain status. I would use this in my code(and i'm not the only one, check the comments here: bug #33698), but i don't know if it's going to be removed in future versions or not.

The documentation is updated.
The concern stated in this bugreport is solved in php7 with return type declarations.
An error will be triggered if you implement two interfaces that have the same method name but have a different return type.

For example:
interface AInterface {
    /** @return Aclass[] */
    public function getObjects(): AClass;
}
interface BInterface {
    /** @return Bclass[] */
    public function getObjects(): BClass;
}

class CClass implements AInterface, BInterface
{
    public function getObjects(): AClass {
       return "???";
    }
}
class AClass {
    public function foo() { echo "foo";}
}
class BClass {
    public function bar() { echo "bar";}
}

The documentation states that for PHP >= 5.3.9, this is the expected behavior: http://php.net/manual/en/language.oop5.interfaces.php

Since the behavior is properly documented, and any change would
require at least discussion on the internals@ mailing list[1] (and
may an RFC), I'm closing this as documentation issue.  

[1] <https://www.php.net/mailing-lists.php>