PHP Header Location Being Circumnavigated

As the title states.

I have PHP header location redirects within directories, which from the logs are being circumnavigated!

Is this possible?

It is such simple code, but it should not be able to go around it!

The code is this

<?php
header("Location: https:// yoursitehere.whatever");
exit();
?>

I have other simple code in different pages which requires a GET (and it must match from a db call ??? blah blah) and if not given correctly, then the redirect happens which has not been moved around.

This is all just simple stuff.

How can someone bypass it?

It is on line 1 of the file.

Thanks for any advice.

Oh and it is not bots, spiders or robots. All of those are no issue.

needs more info. which php version, which webserver, etc. logs would also be nice to see what the issue is.