Dante forgets directory variables (dante-methods) from time to time

[qrilka]

I have a Stack project and in .dir-locals.el I have ((nil . ((dante-methods . (stack))))). When I load a file first time everything works fine but when I go to that file after some delay dante mode breaks and shows "Danté:stopped" on the status bar. After killing Dante with dante-destroy and invoking dante-restart when I run dante-info I get a buffer with error message saying that Danté failed to load a nix-shell (not Stack). At first just checking a directory variable failed and entering C-h v dante-mode was failing with funcall-interactively: Wrong type argument: listp, "/home/qrilka/ws/h/hatrace/", after calling (hack-dir-local-variables-non-file-buffer) I see a proper description:

dante-methods is a variable defined in ‘dante.el’.
Its value is (stack)
Original value was 
(styx new-impure-nix new-nix nix impure-nix new-build nix-ghci stack mafia bare-cabal bare-ghci)
Local in buffer Hatrace.hs; global value is (stack)

  This variable’s value is directory-local, set by the file
  ‘/home/qrilka/ws/h/hatrace/.dir-locals.el’.
  This variable is safe as a file local variable if its value
  satisfies the predicate ‘listp’.

Documentation:
Keys in ‘dante-methods-alist’ to try, in order.
Consider setting this variable as a directory variable.

You can customize this variable.

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Would be grateful for any help to debug the situation as currently the only workaround I have is restarting Emacs every time which is annoying.