I opened an AAA session and the architect located an open issue on this topic.
The VTL parsing behavior for Web Services connectors differs between non-SaaS and SaaS configurations. In the SaaS connector, the @ symbol must be escaped with a ` (grave accent) symbol.
The correct graph paging configuration for non-SaaS connectors is:
TERMINATE_IF $response.['@odata.nextLink']$ == NULL
$endpoint.fullUrl$ = $response.['@odata.nextLink']$
The correct graph paging configuration for SaaS connectors is:
TERMINATE_IF $response.['`@odata.nextLink']$ == NULL
$endpoint.fullUrl$ = $response.['`@odata.nextLink']$
I hope that helps someone!