Logic issue with only an institution value in the params

An AbstractController::DoubleRenderError occurred while GET </auth/login?inst=val1> was processed by sessions#new
Exception
Render and/or redirect were called multiple times in this action. Please note that you may only call render OR redirect, and at most once per action. Also note that neither redirect nor render terminate execution of the action, so if you want to exit an action after redirecting, you need to do something like "redirect_to(...) and return".
Hostname
gsp04
Backtrace
app/controllers/sessions_controller.rb:45:in `new'
Data
server: www.galileo.usg.edu