An include parameter that reached three levels

A documented depth limit of two, and a consumer requesting three.

GET /api/v2/orders?include=customer.addresses.region

→ 400 Bad Request
  "Include depth 3 exceeds the maximum of 2.
   Permitted: lines, refunds, customer,
   customer.addresses"

the consumer's reason: they needed a region name and
were resolving it with a second request per address.

what we did: added region as a field on the address
rather than raising the depth limit.

A depth limit that produces a request for depth three is a signal that a field is missing rather than that the limit is wrong, and raising it would have been the easy answer and a permanent one. The error message listing the permitted values is what turned this into a conversation rather than a support ticket.