error when cancel adding a new card

Go to add a new card page

choose a card type other than the default one (basic)

click cancel button

application error occurs

I noticed it since the first time I deployed WAGN for internal use (v1.5.1). First I thouhgt I failed to configure the environment properly, but after I tried on wagn.org, the same error occured. It's not important but it does annoy people everytime we want to cancel something...

excuse me... how to attach a picture in a ticket...