Have you ever seen a device with different physical addresses when connected to a 2.4Ghz or 5Ghz Wireless network?

I have a user having issues with our client-locked VPN. Macbook Pro.

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With 2.4 Ghz

Wireless LAN adapter Wi-Fi: Connection-specific DNS Suffix . : mynet
Description . . . . . . . . . . . : Intel(R) Dual Band Wireless-AC 8265
Physical Address. . . . . . . . . : A2-D8-6A-FB-B1-50

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With 5 Ghz
Wireless LAN adapter Wi-Fi: Connection-specific DNS Suffix . : mynet
Description . . . . . . . . . . . : Intel(R) Dual Band Wireless-AC 8265
Physical Address. . . . . . . . . : 00-21-6A-F6-8B-5A

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Googling thus far hasn't yielded much - any ideas?