Ruby 2.4.1 is installed, yet can't be selected with asdf

`asdf-ruby` works on my machine well, but not for 2.4.1 . Somehow it yells that 2.4.1 doesn't exist even though it does.
I updated both `asdf` and `asdf-ruby` to the newest version and it didn't help. Removing and installing 2.4.1 again also didn't help.

Anybody ever had this issue? Any idea how to fix it?

```sh
asdf --version
# v0.8.0

asdf plugin list --urls --refs
# ruby https://github.com/asdf-vm/asdf-ruby.git master 101e86a

asdf list ruby
# 2.4.1
# 2.5.7
# 2.6.6

asdf shell ruby 2.6.6
ruby -v
# ruby 2.6.6p146 (2020-03-31 revision 67876) [x86_64-darwin19]

asdf shell ruby 2.5.7
ruby -v
# ruby 2.5.7p206 (2019-10-01 revision 67816) [x86_64-darwin19]

asdf shell ruby 2.4.1
ruby -v
# No preset version installed for command bundle
# Please install a version by running one of the following:
#
# asdf install ruby 2.4.1
#
# or add one of the following versions in your config file at /Users/slimak/.tool-versions
# ruby 2.5.7
# ruby 2.6.6
# ruby 2.4.1p111 (2017-03-22 revision 58053) [x86_64-darwin19]
```