Why does Bitrix cache $_REQUEST?

Question

1C-Bitrix

Tell me why Bitrix can cache the "$_REQUEST" value? In the NC rules is "SECTION_CODE" to determine the address of the section. I'm making a list of sections with links, but when following the link, the value of "$_REQUEST['SECTION_CODE']" remains unchanged. If you clear the cache (or disable the component cache), the value changes.