I've been having this oddball problem with my mANTbox 19s and Metal 52ac where when in station mode, they can't get DHCP on a network when the access point is not from Mikrotik. I tried everything including factory resets and updating to 6.48. Weirdly, they get DHCP when in station-pseudobridge mode, and I can configure the gateway and IP manually and get network access in station mode. Additionally, when connecting the two devices to each other, DHCP works just fine. Could this be some weird 802.11 incompatibility problem? The security profiles aren't the problem because the same happens when using the default (open) profile on an open network. QuickSet also doesn't help.
One more thing: When I have a Mik device as an AP, the DHCP client gets an address right away so the problem is purely in wireless.