bad signatures preventing TL2020 update

[AC]

As of this morning (~6 AM EST, Sun, May 3) attempts to update with 

tlmgr update --self --all

results in the following type of error:

--- cut here ---

signature verification error of /axiomatic/data/texlive/2020/tlpkg/texlive.tlpdb.fbf22200f2de81d918aad63c374280dc from http://mirror.las.iastate.edu/tex-archive/systems/texlive/tlnet/tlpkg/texlive.tlpdb: cryptographic signature verification of
  /tmp/gVDsrHihXv/ulyFfzWvPa
against
  http://mirror.las.iastate.edu/tex-archive/systems/texlive/tlnet/tlpkg/texlive.tlpdb.sha512.asc
failed. Output was:
gpg: Signature made Fri 01 May 2020 07:58:00 PM EDT
gpg:                using RSA key 4CE1877E19438C70
gpg: BAD signature from "TeX Live Distribution <tex-live at tug.org>" [ultimate]

Please try from a different mirror and/or wait a few minutes
and try again; usually this is because of transient updates.
If problems persist, feel free to report to texlive at tug.org.

--- end ---

The same happens with other mirrors, such as

http://ctan.mirrors.hoobly.com/systems/texlive/tlnet

and 

http://mirror.ctan.org/systems/texlive/tlnet