Getting Cookie Overflow in rails application(REDMINE)

ActionDispatch::Cookies::CookieOverflow (ActionDispatch::Cookies::CookieOverflow):
actionpack (4.2.8) lib/action_dispatch/middleware/cookies.rb:529:in `[]='

I am getting this error when hitting redmine rest api. The simple get api like url1 works fine but when it come to complex url as url2 the application throws cookie overflow.

url1: localhost:3000/issues.json?page=1&limit=100
url2: https://deerminetest.deerwalk.com/issues.json?key=292fe116d13d5f5db8a0e3f2b031f1e57ad1c882&f[]=project_id&op[project_id]=!&v[project_id][]=505&f[]=project_id&op[project_id]=!&v[project_id][]=478&f[]=project_id&op[project_id]=!&v[project_id][]=366&f[]=project_id&op[project_id]=!&v[project_id][]=419&f[]=project_id&op[project_id]=!&v[project_id][]=343&f[]=project_id&op[project_id]=!&v[project_id][]=345&f[]=project_id&op[project_id]=!&v[project_id][]=512&f[]=project_id&op[project_id]=!&v[project_id][]=487&f[]=project_id&op[project_id]=!&v[project_id][]=473&f[]=project_id&op[project_id]=!&v[project_id][]=509&f[]=project_id&op[project_id]=!&v[project_id][]=520&f[]=project_id&op[project_id]=!&v[project_id][]=404&f[]=project_id&op[project_id]=!&v[project_id][]=440&f[]=project_id&op[project_id]=!&v[project_id][]=389&f[]=project_id&op[project_id]=!&v[project_id][]=467&f[]=project_id&op[project_id]=!&v[project_id][]=501&f[]=project_id&op[project_id]=!&v[project_id][]=474&f[]=project_id&op[project_id]=!&v[project_id][]=471&f[]=project_id&op[project_id]=!&v[project_id][]=480&f[]=project_id&op[project_id]=!&v[project_id][]=507&f[]=project_id&op[project_id]=!&v[project_id][]=383&f[]=project_id&page=1&limit=100

I have not stored anything but username, cas ticket in session as:

 request.session['cas'] = { 'user' => user, 'ticket' => ticket, 'extra_attributes' => [] }

I have searched for the solution in many forums. All said donot save unnecessary data but all i am saving are username and cas ticket. When i print session this is the result:

puts(session.to_hash)

{"session_id"=>"fbe61cf9fd1c2ef0111d5d84a1a374c2", "cas"=>{"user"=>"user@gmail.com", "ticket"=>"ST-27189-R20MW7GBWaLWNJvl1aMi-localhost", "extra_attributes"=>[]}}

But when inspect session as below i get loads of gibberish data like below:

puts(session.inspect)

[result]: https://textsaver.flap.tv/lists/3caw "Click here for session.inspect output"

Since i am a newbie and just starting ruby on rails any suggestions will be highly appreciated. Thank You.