We have many subscriptions in our tenant and the subscription list endpoint (https://management.azure.com/subscriptions?api-version=2018-01-01) is only returning partial results during the initial call. If azbrowse should display all available subscription it needs to handle nextLink paging or use a SDK which automatically does so.
{
"value": [
{...}
],
"nextLink": "https://management.azure.com/subscriptions?api-version=2018-01-01&%24skiptoken=eyJuZXh0TW..."
}