Bug of PDBookmarkGetByTitleASText

I am using Acrobat SDK to develop an Acrobat using C++.

The following code does not pop up HERE for some files.

it should pop up for any files,

I cannot upload my pdf here, but I think it is a bug.

   PDDoc doc=AVDocGetPDDoc(AVAppGetActiveDoc());
   PDBookmarkroot=PDDocGetBookmarkRoot(doc);
   ASTexttitle=ASTextNew();
   //haschildren
   PDBookmarkGetTitleASText(PDBookmarkGetFirstChild(root),title);
   PDBookmarknewBookmark=PDBookmarkGetByTitleASText(root,title,1);
   if(PDBookmarkIsValid(newBookmark))AVAlertNote("HERE");
   ASTextDestroy(title);