Advertising setAppearance seems not to work

[madmanguruman]

ESP-IDF 5.5 / esp-nimble-cpp 2.3.3 / ESP32S3-WROOM-N8R2

I am coding a peripheral / broadcaster on an ESP32S3 and am attempting to advertise with the Generic HVAC appearance type (0x0600) and a custom name.

Regardless of what value I provide to the setAppearance function, all BLE clients (Nordic, LightBlue, BLE Tester) report the value as 0 / unknown.

pServer = NimBLEDevice::createServer();
fcAdvertising = pServer->getAdvertising();
advertisementData.setName("Generic HVAC Device", true); // true for complete name
advertisementData.setAppearance(0x0600); // Generic HVAC
fcAdvertising->setAdvertisementData(advertisementData);
...
fcAdvertising.start();

I also tried the un-shifted value for Generic HVAC (0x0018) and that also resulted in 0 / unknown.