Agile Web Development with Rails 8: Bundler::StubSpecification

Just finished installing ruby 3.3.6 and rails 8.0.0 on ubuntu 24.04 LTS.

‘rails new demo’ seems to be building correctly but is throwing a ‘missing extensions’ warning for each gem being used. Example:

"source locally installed gems is ignoring #<Bundler::StubSpecification name= version= platform=ruby> because it is missing extensions.

This is a new one for me. Did I miss an install step?