next-error and previous-error not working in second and consecutive calls to helm-ag

[uwethuemmel]

• Emacs version: 25.2
• Operating system: Mac OS X 10.11.6
• Search command(ag, pt, ack etc) and version
• Last value of helm-ag--last-command: "ag" "--nocolor" "--nogroup" "sigma"

Actual behavior

After the first call to helm-ag when using C-c C-e in the helm buffer with search results the message "Making helm-ag--default-directory local to helm-ag-edit while let bound!" is displayed and M-x: next-error jumps to the next search result and opens the corresponding buffer.

After C-c C-k (or C-c C-c): if I search again, and use C-c C-e in the new helm buffer, when now using M-x: next-error, I get the message "Marker points into wrong buffer: #" and nothing further happens (hence no jumping to the next line of search results and no display of the respective buffer)

I am using a clean version of emacs with no extra packages installed besides helm and helm-ag and without any further customizations.

Expected behavior

What works in the first call to helm-ag should also work in the second call.

Steps to reproduce

M-x: helm-ag enter search term C-c C-e M-x: next-error C-c C-k

Repeat the above.