get_the_category display problem

Is get_the_category modified and updated?
The content of the page using this function is now found to be problematic, some articles display the category id, and some articles do not display the category id. The print result of var_dump is only the output result of some articles.

This page was normal before, is it a bug caused by updating to the latest version?

<?php
     foreach((get_the_category()) as $category){
           echo $category->term_id . ' ' ;
     }
?>