Subnet id limits are not enforced

Kea 9.11: According to the ARM "Subnet IDs must be greater than zero and less than 4294967295."

However no configuration error appears to be generated when a subnet with an id greater than this is used?

{ 
   "id": 10255255025,
   "subnet": "10.0.0.0/24",
   "pools": [ 
   { 
      "pool": "10.0.0.50 - 10.0.0.201" } ]
   }
]

Subnet id 10255255025 becomes 1665320433.

2021-09-01 09:16:29.465 DEBUG [kea-dhcp4.hosts/4035250.140148899886976] HOSTS_CFG_GET_ONE_SUBNET_ID_ADDRESS4 get one host with reservation for subnet id 1665320433 and IPv4 address 10.0.0.160

kea-lease4.csv:

address,hwaddr,client_id,valid_lifetime,expire,subnet_id,fqdn_fwd,fqdn_rev,hostname,state,user_context
10.0.0.50,98:ee:cb:4c:22:8f,,600,1631520296,1665320433,0,0,,0,

RT #19141