Django view called twice Firefox

Question

EDIT: This question fixed my issue: What happens when no response is received for a request? I'm seeing retries

I have a weird issue. I have a Django application. The frontend has two forms. I submit the forms together via the same Ajax post method

    // code to get and format form data to get into the format I need in the backend

    var webURL = "showFormOutput";
    $.post(webURL,
        dataToSend,
        callback
          ).fail(function(jqXHR, textStatus, errorThrown)
            {
                console.log("Status: " + textStatus);
                console.log("Error: " + errorThrown);
            });

In the Django view corresponding to that url, I do the following:

1. Print a message "View function" to log that I am in the view.
2. Parse the post data and put it into appropriate variables. Pass these variables to a Python function in a separate file. Let us call this function getQueryResults.
3. Create two Postgres queries (for two forms) using these variables. Print a log message "Query created".
4. Use Python's threading module to execute these two queries. I run the following line twice to create two separate threads for the two queries threading.Thread(target=threadFunction, args=(query,).start()
5. Log in the threadFunction "Query result ready" when the postgres query returns.

This is a long running query - takes up to ten minutes.

In Chrome, this works perfectly. However, in Firefox (and Safari too I think), I get the following issues:

1. When using Firefox, I can see in pg_stat_activity that two queries are running as expected. However, after about 5 minutes, there are FOUR queries running i.e. two more of the SAME query are started.
2. This is reflected in my logs also. I get the messages "View Function" and "Query Created" printed AGAIN. This means that somehow, the execution restarted from the view. This happens even on increasing the http.response.timeout to 30000.
3. Sometimes, Firefox just goes to the fail() case of the $.post and textStatus just says "Error" and errorThrown is blank. Sometimes, it prints my query results as expected but it waits for the second set of queries to finish. I thought it might be an issue with my Python threads but it makes no sense to have the whole view executed again since the threads never call the view anywhere! On the client side, the POST request doesn't seem to be sent again.

Notes: I am using django's filesystem-based cache to cache the query results. Could this be an issue? The second duplicate set of queries turn up even before the first actual set return results so I doubt this is the issue though.

Has anyone got any idea why using Firefox would result in my view being called twice?