After helm-ag is finished, the first call to helm-next-line doesn't work

[angrybacon]

• GNU Emacs 24.5.1 (x86_64-apple-darwin15.2.0, Carbon Version 157 AppKit 1404.34)
• OS X "El Capitan" 10.11.4
• ag 0.31.0

Last value of helm-ag--last-command

("ag" "--nocolor" "--nogroup" "--ignore" "TAGS" "--ignore" ".#" "--ignore" ".o" "--ignore" "~" "--ignore" ".bin" "--ignore" ".lbin" "--ignore" ".so" "--ignore" ".a" "--ignore" ".ln" "--ignore" ".blg" "--ignore" ".bbl" "--ignore" ".elc" "--ignore" ".lof" "--ignore" ".glo" "--ignore" ".idx" "--ignore" ".lot" "--ignore" ".fmt" "--ignore" ".tfm" "--ignore" ".class" "--ignore" ".fas" "--ignore" ".lib" "--ignore" ".mem" "--ignore" ".x86f" "--ignore" ".sparcf" "--ignore" ".dfsl" "--ignore" ".pfsl" "--ignore" ".d64fsl" "--ignore" ".p64fsl" "--ignore" ".lx64fsl" "--ignore" ".lx32fsl" "--ignore" ".dx64fsl" "--ignore" ".dx32fsl" "--ignore" ".fx64fsl" "--ignore" ".fx32fsl" "--ignore" ".sx64fsl" "--ignore" ".sx32fsl" "--ignore" ".wx64fsl" "--ignore" ".wx32fsl" "--ignore" ".fasl" "--ignore" ".ufsl" "--ignore" ".fsl" "--ignore" ".dxl" "--ignore" ".lo" "--ignore" ".la" "--ignore" ".gmo" "--ignore" ".mo" "--ignore" ".toc" "--ignore" ".aux" "--ignore" ".cp" "--ignore" ".fn" "--ignore" ".ky" "--ignore" ".pg" "--ignore" ".tp" "--ignore" ".vr" "--ignore" ".cps" "--ignore" ".fns" "--ignore" ".kys" "--ignore" ".pgs" "--ignore" ".tps" "--ignore" ".vrs" "--ignore" ".pyc" "--ignore" "*.pyo" "--ignore" ".idea/" "--ignore" ".eunit/" "--ignore" ".git/" "--ignore" ".hg/" "--ignore" ".fslckout/" "--ignore" ".bzr/" "--ignore" "_darcs/" "--ignore" ".tox/" "--ignore" ".svn/" "--ignore" ".stack-work/" "--ignore" "auto-save-list/" "--ignore" "elpa/" "--ignore" "SCCS" "--ignore" "RCS" "--ignore" "CVS" "--ignore" "MCVS" "--ignore" ".svn" "--ignore" ".git" "--ignore" ".hg" "--ignore" ".bzr" "--ignore" "_MTN" "--ignore" "_darcs" "--ignore" "{arch}" "--" "setq")

Using ag over my project with Projectile, I looked for "setq". The candidates show correctly. Two scenarios:

1. The first time I hit either down or up, nothing visually happens. Every other command works fine afterwards.
2. If however I use helm-follow-action-forward or helm-follow-action-backward directly instead, I see the preview as expected. After that, I am in the first scenario's situation ie. I have to do my command twice for it to kick in.

Here is my Helm setup (I only removed the change of faces):

(use-package helm
  :defer 1
  :config
  (helm-mode 1)
  (setq-default
   helm-always-two-windows t
   helm-display-header-line nil
   helm-mode-line-string nil
   helm-split-window-default-side 'left))

(use-package helm-ag
  :config (setq-default helm-ag-show-status-function nil))