Unknown encoding when Parsing documentation for http_parser.rb-0.6.0

Hello,
I am getting an unknown encoding message during the install of Jekyll (sudo gem install -n /usr/local/bin/ jekyll) on OSX 10.14. The warning message is:

Parsing documentation for http_parser.rb-0.6.0
unknown encoding name "chunked\r\n\r\n25" for ext/ruby_http_parser/vendor/http-parser-java/tools/parse_tests.rb, skipping*
Installing ri documentation for http_parser.rb-0.6.0

Is this to be expected? Should I file a bug?