_gcl_au is a advertising cookie. Under Art. 5(3) ePrivacy Directive and the GDPR, it must not be set before the visitor has given prior, informed, freely-given consent.

If your scanner finds _gcl_au on a page before the visitor interacts with your consent banner, that's a violation — the cookie loaded without a legal basis.

Fix: gate the script that sets this cookie behind your CMP, so it only fires after the relevant consent category is accepted.