LOCALE woes in Ubuntu 24.04 on WSL

pyenv claims issues with LOCALE in Ubuntu 24.04 running in WSL on Windows 11.

.pyenv/libexec/pyenv-help: line 29: warning: setlocale: LC_CTYPE: cannot change locale (C.UTF-8): No such file or directory

It worked correctly in the past. What is this? How do I fix it?