diff --git a/homeassistant/components/mqtt/sensor.py b/homeassistant/components/mqtt/sensor.py
index 46d475fcee8..def9bb209f7 100644
--- a/homeassistant/components/mqtt/sensor.py
+++ b/homeassistant/components/mqtt/sensor.py
@@ -138,12 +138,9 @@ def validate_sensor_state_and_device_class_config(config: ConfigType) -> ConfigT
         device_class in DEVICE_CLASS_UNITS
         and unit_of_measurement not in DEVICE_CLASS_UNITS[device_class]
     ):
-        _LOGGER.warning(
-            "The unit of measurement `%s` is not valid "
-            "together with device class `%s`. "
-            "this will stop working in HA Core 2025.7.0",
-            unit_of_measurement,
-            device_class,
+        raise vol.Invalid(
+            f"The unit of measurement '{unit_of_measurement}' is not valid "
+            f"together with device class '{device_class}'"
         )
 
     return config
diff --git a/tests/components/mqtt/test_sensor.py b/tests/components/mqtt/test_sensor.py
index ea1b7e186e2..775af035b95 100644
--- a/tests/components/mqtt/test_sensor.py
+++ b/tests/components/mqtt/test_sensor.py
@@ -21,7 +21,7 @@ from homeassistant.const import (
     UnitOfTemperature,
 )
 from homeassistant.core import Event, HomeAssistant, State, callback
-from homeassistant.helpers import device_registry as dr, issue_registry as ir
+from homeassistant.helpers import device_registry as dr
 from homeassistant.helpers.typing import ConfigType
 from homeassistant.util import dt as dt_util
 
@@ -71,7 +71,6 @@ from .common import (
 
 from tests.common import (
     MockConfigEntry,
-    async_capture_events,
     async_fire_mqtt_message,
     async_fire_time_changed,
     mock_restore_cache_with_extra_data,
@@ -892,48 +891,11 @@ async def test_invalid_unit_of_measurement(
     caplog: pytest.LogCaptureFixture,
 ) -> None:
     """Test device_class with invalid unit of measurement."""
-    events = async_capture_events(hass, ir.EVENT_REPAIRS_ISSUE_REGISTRY_UPDATED)
     assert await mqtt_mock_entry()
     assert (
-        "The unit of measurement `ppm` is not valid together with device class `energy`"
+        "The unit of measurement 'ppm' is not valid together with device class 'energy'"
         in caplog.text
     )
-    # A repair issue was logged
-    assert len(events) == 1
-    assert events[0].data["issue_id"] == "sensor.test"
-    # Assert the sensor works
-    async_fire_mqtt_message(hass, "test-topic", "100")
-    await hass.async_block_till_done()
-    state = hass.states.get("sensor.test")
-    assert state is not None
-    assert state.state == "100"
-
-    caplog.clear()
-
-    discovery_payload = {
-        "name": "bla",
-        "state_topic": "test-topic2",
-        "device_class": "temperature",
-        "unit_of_measurement": "C",
-    }
-    # Now discover an other invalid sensor
-    async_fire_mqtt_message(
-        hass, "homeassistant/sensor/bla/config", json.dumps(discovery_payload)
-    )
-    await hass.async_block_till_done()
-    assert (
-        "The unit of measurement `C` is not valid together with device class `temperature`"
-        in caplog.text
-    )
-    # Assert the sensor works
-    async_fire_mqtt_message(hass, "test-topic2", "21")
-    await hass.async_block_till_done()
-    state = hass.states.get("sensor.bla")
-    assert state is not None
-    assert state.state == "21"
-
-    # No new issue was registered for the discovered entity
-    assert len(events) == 1
 
 
 @pytest.mark.parametrize(