Came across this while investigating puppet failed runs in T228878: Reduce Icinga alert noise. Looks like /var/log/apache2/error.log has repeated warnings like these:
App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:15: warning: already initialized constant Apr1Md5::DIGEST_LENGTH App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:15: warning: previous definition of DIGEST_LENGTH was here App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:27: warning: already initialized constant Apr1Md5::SALT_CHARS App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:27: warning: previous definition of SALT_CHARS was here App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:15: warning: already initialized constant Apr1Md5::DIGEST_LENGTH App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:15: warning: previous definition of DIGEST_LENGTH was here App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:27: warning: already initialized constant Apr1Md5::SALT_CHARS App 32255 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:27: warning: previous definition of SALT_CHARS was here App 6909 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:15: warning: already initialized constant Apr1Md5::DIGEST_LENGTH App 6909 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:15: warning: previous definition of DIGEST_LENGTH was here App 6909 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:27: warning: already initialized constant Apr1Md5::SALT_CHARS App 6909 stderr: /etc/puppet/modules/wmflib/lib/puppet/parser/functions/htpasswd.rb:27: warning: previous definition of SALT_CHARS was here App 32255 stderr: /usr/lib/ruby/vendor_ruby/puppet/pops/parser/lexer2.rb:383: warning: character class has '-' without escape: /[a-zA-Z0-9-_]+/ App 32255 stderr: /usr/lib/ruby/vendor_ruby/puppet/pops/parser/lexer2.rb:383: warning: character class has '-' without escape: /[a-zA-Z0-9-_]+/ App 32255 stderr: /usr/lib/ruby/vendor_ruby/puppet/pops/types/types.rb:1586: warning: character class has '-' without escape: /[a-zA-Z0-9-_]+/ App 32255 stderr: /usr/lib/ruby/vendor_ruby/puppet/pops/types/types.rb:1586: warning: character class has '-' without escape: /[a-zA-Z0-9-_]+/