Your understanding is correct.
I could not see this issue with a project build with PC-4.0 and 4.2 with a Silicon Generated MAC Address at my side.
Which BLE device are you using ?
Could you try with a different device and confirm as well?
Which BLE Component version are you using in both the projects? ( Put the cursor on BLE component or open the BLE component datasheet and check)
In case of latest versions of BLE component from BLE v3.0 the device address is generated using the factory programmed die X/Y location, wafer ID and lot ID of the silicon. But in case of old versions of BLE component such as BLE v2.1 the device address is generated based on die X/Y location, wafer ID of the silicon only it does not include lot ID of the silicon.
Thanks, PSYU. This does appear to be the case.