Both products are Apple, can a MAC (using Apple's MAC randomisation) even be attributed to a specific type of device (Mac vs iPhone)?
Unlikely it's strictly MAC address pattern based and as AlphaJohn points out rather another means of linking the Mac address to a type of device once off and then blacklisting it.
Could very well not even be Mac address at all and simply some intelligent scanning to determine device type or transparent proxy in the middle picking up the browser etc.
Apple devices announce themselves via Bonjour as well.
Many ways to go about it.
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The radomization you speak of rather relates to Mac address reading FROM the Apple device. So you can't use Wireless Scan tools based on Mac address from your iPhone any more.
Things like Fing now use other means to detect type of device and are still pretty accurate. But they might just not be able to tell you exactly who the device belongs to, but in most cases still tells you what it is.