Well, apparently, (I guesstimate) since (some time around) CGI::Application 3.x it is no longer recommended to reuse CGI::Application objects, no longer recommended to call run repeatedly, as Bug #72909 for CGI-Application: persistence issues says CGI::Application is designed to have a new object created on each request. which is an assumption various ::Plugins and extensions make, so its best to play along and not reuse an object and not ->run ->run ->run
You probably discovered this on your own :)