Hi,
Thanks for the question. You can refer below link for the entire procedure which is using 1Gbps speed settings in the Leaf Access policy group for Dell Chassis to ACI infrastructure with B22 expansion modules. Since you suspect it to be a cosmetic issue. We would request you to raise a TAC case to know the previous experiences with the B22's expansion modules with Cisco ACI.
https://www.cisco.com/c/en/us/support/docs/cloud-systems-management/application-policy-infrastructure-controller-apic/200529-Configure-a-Fabric-Extender-with-Applica.html
If you find my reply solved your question or issue, kindly click the 'Accept as Solution' button and vote it as helpful.
You can also learn more about Cisco ACI through our live Ask the Experts (ATXs) session. Check out Cisco ACI ATXs Resources [https://community.cisco.com/t5/data-center-and-cloud-knowledge/cisco-aci-ask-the-experts-resources/ta-p/4394491] to view the latest schedule for upcoming sessions, as well as the useful references, e.g. online guides, FAQs.
Thanks and regards,
Tarakesh Jetti
Customer Success Specialist - CX