Subnet registration block 7105263 - registration price decreased instead of expected increase

[dougsillars]

Describe the bug

we were looking at the cahrt, and saw after a registrtaion, the price went *down*. Expected it would go up.

To Reproduce

Here is the latest registration

  {
      "block_number": 7105263,
      "timestamp": "2025-12-15T17:49:12Z",
      "netuid": 108,
      "registration_cost": "391200311368",
      "recycled_at_registration": "164584441837",
      "owner": {
        "ss58": "5HDuqw9fkqG3xdm1yZA8dfKeLBnZhg138xiMwnYQdBeLfytT",
        "hex": "0xe432ba9837ab4f8ed3dde43c76d55d86c9ed33ea1d65ac8aec3e9082ba9b0679"
      },
      "registered_by": {
        "ss58": "5HDuqw9fkqG3xdm1yZA8dfKeLBnZhg138xiMwnYQdBeLfytT",
        "hex": "0xe432ba9837ab4f8ed3dde43c76d55d86c9ed33ea1d65ac8aec3e9082ba9b0679"
      }
    },

look at the current price - it has dropped.

Here is the taostats API:

    {
      "block_number": 7105466,
      "timestamp": "2025-12-15T18:31:12Z",
      "registration_cost": "330585313687",
      "is_purchase": false
    },
    {
      "block_number": 7105263,
      "timestamp": "2025-12-15T17:49:12Z",
      "registration_cost": "331168883674",
      "is_purchase": false
    },
    {
      "block_number": 7105262,
      "timestamp": "2025-12-15T17:48:48.001Z",
      "registration_cost": "391200311368",
      "is_purchase": true
    },

Expected behavior

Price go up

(but seriously - when a subnet is registered the cost for subsequent registrations is supposed to increase)

Screenshots

No response

Environment

MacOS

Additional context

No response

[JohnReedV]

must be because of the halving

subtensor/pallets/subtensor/src/coinbase/root.rs

Line 574 in 8834a7c

let halving: I64F64 = block_emission