Graph API returns the same group multiple times when doing initial delta sync

In our Azure AD directory one of our groups has 6 members. When calling the /groups/delta endpoint without a syncToken the result set includes the aforementioned group twice. Once on the first page with 2 members, another time on the second page with 4 members. Together the memberships match the expected ones.

Is this an expected behavior and we should aggregate on our side, or is it a bug?

I had some intermittent issues with the same group being returned multiple times just after modification, however in this case the issue happens every time on our tenant. Since the issue started occurring no changes to directory data were done on the tenant.

Group data on page 1:

{
  "description": null,
  "displayName": "crowd-administrators",
  "id": "a6eba1a3-e348-4881-842a-53c1809c10cc",
  "members@delta": [
    {
      "@odata.type": "#microsoft.graph.user",
      "id": "daec3933-f1d1-46f7-b1cb-c99790fa2bf5"
    },
    {
      "@odata.type": "#microsoft.graph.user",
      "id": "7d58fe5f-a832-4548-98e9-5e7250333ac1"
    }
  ]
}

Group data on page 2:

{
  "description": null,
  "displayName": "crowd-administrators",
  "id": "a6eba1a3-e348-4881-842a-53c1809c10cc",
  "members@delta": [
    {
      "@odata.type": "#microsoft.graph.user",
      "id": "d23f7435-70ac-40a9-9bed-c57b5af4915d"
    },
    {
      "@odata.type": "#microsoft.graph.user",
      "id": "4c33e6dc-8efe-4a9b-b6d2-37fef878b6a8"
    },
    {
      "@odata.type": "#microsoft.graph.user",
      "id": "b051725a-69f8-4bb7-b8f4-14548f16afa1"
    },
    {
      "@odata.type": "#microsoft.graph.user",
      "id": "84a66ed7-8559-4fb7-963c-150032e4134e"
    }
  ]
}

In the directory there's only one group with the name crowd-administrators and it has 6 members in total (the same ones as in the output from page 1 and page 2 combined)