Ruby 3.0 RVM error: "Can't check signature: No public key"

Is Ruby 3.0 working yet? I鈥檓 getting weird RVM errors:

e[33;1mSetting environment variables from .travis.ymle[0m
$ export JRUBY_OPTS=--debug
$ export COSMOS_DEVEL=true

e[0K$ rvm get head
e[32mDownloading https://get.rvm.ioe[0m
e[32mVerifying /home/travis/.rvm/archives/rvm-installer.asce[0m
gpg: Signature made Tue 23 Jul 2019 09:59:45 PM UTC using RSA key ID 39499BDB
gpg: Can't check signature: No public key
e[31mWarning, RVM 1.26.0 introduces signed releases and automated check of signatures when GPG software found. Assuming you trust Michal Papis import the mpapis public key (downloading the signatures).

GPG signature verification failed for '/home/travis/.rvm/archives/rvm-installer' - ''! Try to install GPG v2 and then fetch the public key:

    gpg2 --recv-keys 409B6B1796C275462A1703113804BB82D39DC0E3

or if it fails:

    command curl -sSL | gpg2 --import -

the key can be compared with:

NOTE: GPG version 2.1.17 have a bug which cause failures during fetching keys from remote server. Please downgrade or upgrade to newer version (if available) or use the second method described above.
/home/travis/.rvm/scripts/functions/cli: line 243: return: _ret: numeric argument required
e[0Ke[31;1mThe command "rvm get head" failed and exited with 2 during .e[0m

Your build has been stopped.

Which environment is this? Could you link to the build?

Also seem to be having problems with jruby now: Travis CI - Test and Deploy Your Code with Confidence

travis.yml: COSMOS/.travis.yml at 2242d11c427877c57598e852b6847d9829150e9e 路 BallAerospace/COSMOS 路 GitHub

Perhaps you have a bad GPG signature: Return argument error after GPG check failure on bash 路 Issue #4530 路 rvm/rvm 路 GitHub