The name of this flag is terrible but if you read the 2.8 spec.
https://uefi.org/sites/default/files/resources/UEFI_Spec_2_8_A_Feb14.pdf
page 1436.
Says:
EFI_TLS_VERIFY_FLAG_NONE means no additional flags set for hostname validation. Wildcards are supported and they match only in the left-most label.

In the HttpDxe driver we made a change to support wildcards as wildcards are pretty commonly used in web services.
https://github.com/microsoft/mu_basecore/commit/931ff1a45ce13a6a8c3e296f89c6de21f23a17ed#diff-45ead71899abef9932d2697dbd1d8867

There is a lot of noise on this thread but its the best i can find.
https://bugzilla.tianocore.org/show_bug.cgi?id=960

We might need to open a new bugzilla as i think 960 is resolved but is too strict for practical usage.

Thanks
Sean