PDEElementGetBBox returns different value

Hi.

I have developed a plugin which delete the text element from PDF.
In some cases, the value obtained from PDEElementGetBBox return the different value from two text element

at same position within PDDoc objects(objectA and objectB).

objectA makes from objectB.

     const PDDoc objectA = PDDocCreate();
     PDDocCreatePage( objectA, PDBeforeFirstPage, srcrect );
     PDDocReplacePages( objectA, 0, objectB, pagenum, 1, false, NULL, NULL, NULL, NULL );

I Used PDEElementGetBBox to same position text element within objectA and objectB.
but return value(textBBox.left and textBBox.right) is different.

can you tell me reason about this case happened.