MAC address: DE:AD:BE:EF:00:00
That is a locally administered MAC address as indicated by the second-least significant bit in the first octet (0xE = 1110b). As such, it is the responsibility of the user/administrator to make sure it's unique in their network.
AFAIK there's no regulation prohibiting such a practice (there should be) but it may be considered unprofessional. Devices being shipped with identical MAC addresses, without a mechanism to ensure uniqueness (in a network) before use, can be considered broken - but only if these addresses are actually used on an external interface.
What you're seeing is likely just a virtual adapter's dummy address that is presented towards the OS but not actually used anywhere. Mobile devices don't use MAC addresses towards their cell service, they use IMEI addresses. So, MAC duplication problems don't apply here.
(MAC addresses aren't really globally unique any more, but it's the vendor's responsibility to ensure that it's impossible or at least extremely unlikely that two devices with the same address see each other in any network.)