Thanks Kamil.
This article, while not the same approval type, suggests that if the approver and fallback approver are empty that the object will be approved: Approvals for Changes to Entitlements
The same goes for this dev topic:
Entitlement Update Approval
That was what prompted me to ask about having the fallback empty achieving my goal. Since the majority of the entitlements do not have an owner, they would fall through and be approved. The one(s) with an owner would require that approval. Finding that the subprocess didn’t respect the fallback approver from the main process automatically negates that possibility and is what brought up that it might be a bug.
I appreciate the insight and I’ll keep reading up on other possibilities.