A cloud-based service included in Microsoft 365, delivering scalable messaging and collaboration features with simplified management and automatic updates.
It more likely your client, not the GAL itself.
Do you see them in OWA? If not, then you know its the client
Download a new OAB
In Outlook, click File > Account Settings > Download Address Book.
On the Offline address book dialog box that's displayed, make the following selections:
Download changes since last Send/Receive: By default, this check box is selected. Unchecking this box causes a full download of the OAB.
Choose address book: This drop-down list will display the offline address books that are available to you. Depending on what an admin has configured, you might see only one value here (for example, the global address list).
Click OK. The OAB is downloaded and saved on your computer.