On Service Portal, the menu item count does not automatically updates as record watcher. If a user does not have any active requests, then the "Requests" Menu item does not display on the Header Menu:
Steps to Reproduce
1) Open the Service Portal as System Administrator
2) Order an iPad
Observe the Requests count in the header does not update.
This problem was fixed since Jakarta Patch 3, an upgrade is necessary on affected instances.
On earlier releases the workaround consisted of customizing the menuTemplate sp_ng_template record, and the widget being used for header menu. This is not recommended and not supported by ServiceNow.
Related Problem: PRB1108244