You are using Wireshark to view packets captured from HPE Aruba Networking infrastructure, but you...

On Aruba Mobility Controllers, dataplane captures can include wireless frames encapsulated inside GRE (for example, ERM / remote mirroring or tunneled 802.11 data). If Wireshark does not have GRE dissection enabled, these packets may appear as generic IP/UDP payloads, and the inner traffic (client frames) will not decode correctly.

MC dataplane is exactly where GRE-encapsulated user traffic is likely to appear. Enabling GRE in Wireshark allows you to see and decode the inner payload (802.11/Ethernet/IP).

MC control plane traffic is generally not GRE encapsulated data traffic.

For gateways, captures exported as ERM over UDP often require different decoding (e.g., ARUBA_ERM, not generic GRE).

Thus, the most appropriate case to ensure GRE is enabled is when the capture came from the MC dataplane → Option D.