I’ve confirmed the behaviour in https://github.com/appium/ruby_lib/pull/646/files and tap works well for NATIVE_APP. If webview context, current behaviour is expected: https://github.com/appium/appium/issues/9040 . You can find Touch Actions and Mobile Web for web context.
For available_contexts, I guess you should call driver.available_contexts. Could you try to driver.available_contexts after driver = appium.start_driver?
@mark0203