Crash when initiating an object of a class from static lib

Question

I'm compiling a 3rd party code (which is given as a VS solution) to a static library. This code has one class which is for simplification looks like this:

Sample.h:

class Sample
{
 public:
    Sample();
    ~Sample();
    void Foo();
 private:
    // some private members.
};

Sample.cpp:

Sample::Sample()
{
}
Sample::~Sample()
{
}
void Sample::Foo()
{
    //Do something...
}

This class compiles to a static library Sample.lib

Now in my main program I want to initiate an object of Sample:

MyFile.cpp:

#include "Sample.h"
//some code.
Sample* sample = new Sample();
//some code

and at some point when the program continues I'm getting a crash. The place where it crashes isn't consistent:

Unhandled exception at 0x770A0BFE (ntdll.dll) in MyApplication.exe: 0xC0000005: Access violation reading location 0xFFFFFFF8.

But when I put the Sample class in a wrapper class (in the same solution of the static lib): Wrapper.cpp:

class Wrapper
{
public:
    Wrapper()
    {
        _sample = new Sample();
    }
    ~Wrapper()
    {
        delete sample;
    }
    void Foo()
    {
       _sample->Foo();
    }
private:
    Sample* _sample;
}

and then initialize the Wrapper class in my program:

MyFile.cpp:

#include Sample.h
//some code.
Wrapper* wrapper = new Wrapper();
//some code

It works well and I'm not getting any crash.

Does anybody has a clue? Thanks!