Ruby on Rails daylight-saving detection does not work in recent `ruby:2.7.1-alpine` container

Ruby on rails with recent ruby:2.7.1-alpine container, breaks timezone daylight-saving support:

irb(main):004:0> Time.zone.to_s
=> "(GMT+01:00) Europe/Berlin"
irb(main):005:0> Time.zone.parse("2020-08-27").zone
=> "CEST"
irb(main):006:0> Time.zone.parse("2020-12-27").zone
=> "CEST"

2020-12-27 should actually be CET because of daylight saving. On local ruby installation and previous container builds it used to work and would returns:

irb(main):006:0> Time.zone.to_s
=> "(GMT+01:00) Europe/Berlin"
irb(main):007:0> Time.zone.parse("2020-08-27").zone
=> "CEST"
irb(main):008:0> Time.zone.parse("2020-12-27").zone
=> "CET"

The Dockerfile looks as follows:

FROM ruby:2.7.1-alpine

# Add basic packages
RUN apk add --update --no-cache \
      build-base \
      python2 \
      postgresql-dev \
      git \
      nodejs \
      yarn \
      tzdata \
      file \
      # Image processing resources
      gobject-introspection-dev \
      poppler-dev \
      # Test Resources
      chromium-chromedriver \
      chromium \
      harfbuzz \
      nss

WORKDIR /app

# Install standard gems
COPY Gemfile* /app/
RUN gem install bundler && \
    bundle config --global frozen 1 && \
    bundle config --local build.sassc --disable-march-tune-native && \
    bundle install -j4 --retry 3

# Install standard Node modules
COPY package.json yarn.lock /app/
RUN yarn install

ONBUILD COPY . ./

Does anybody knows more about the internals? Is this a rails or ruby or alpine package problem. Any help would be great!

UPDATE

I could reproduce the behavior with a clean docker like:

docker run -it ruby:2.7.1-alpine  /bin/sh

   0 apk add --update --no-cache build-base sqlite-dev nano nodejs yarn tzdata
   1 gem install rails
   2 rails new timzone_test
   3 rails webpacker:install
   4 nano config/application.rb # add config.time_zone = 'Europe/Berlin'
   5 rails console

I have the same issue on this clean install

Loading development environment (Rails 6.0.3.4)
irb(main):001:0> Time.zone.parse("2020-12-27").zone
=> "CEST"

After adding gem 'tzinfo-data' to the Gemfile, everything worked as expected:

Loading development environment (Rails 6.0.3.4)
irb(main):001:0> Time.zone.parse("2020-12-27").zone
=> "CET"

Also see: github.com/tzinfo/tzinfo/issues/120 and github.com/rails/rails/issues/40427