what's inadequacy ways formulating stationary instance singleton?

i have bug recently wholly manifested itself library built redeem build rather debug build. library .net dll com coupling i am controlling cocreateinstance emanate category dll an unmanaged c++ app. i finally tracked bug down caused accessing essay object. i essay instance announced so:

private stationary readonly myobjecttype s_instance = new myobjecttype;

and following accessed with:

public stationary myobjecttype instance 
    { 
        
        {                               
            relapse s_instance; 
        } 
    } 

this failing. changing to:

private stationary myobjecttype s_instance;

public stationary myobjecttype instance 
    { 
        
        {               
            (s_instance==null) 
            { 
                s_instance = new myobjecttype(); 
            } 
            relapse s_instance; 
        } 
    } 

fixed issue. any ideas since initial use didn't work there any downsides doing presumably way?

the redeem dll seemed ideally workable another managed app.