What would cause a Sitecore Form to duplicate submit?

Question

I have created a custom submit based on the below module:

https://www.nishtechinc.com/Blog/2018/April/Send-E-mail-Action-to-Sitecore-9-Forms

It went all hunky dory on my dev machine but when moved to our staging environment it started submitting twice and thus sending two emails. I added some logging to my custom code and it is definitely a submit of the same form as the SessionId, TemplateId etc. are all identical.

During my frantic googling I came across the below question on stack exchange which looks like the same problem but there wasn't an answer given.

Sitecore 9 Forms Custom Submit Model called twice

The bit I am missing is what happens between the form being submitted and it hitting the execute method on my submit action. Any pointers on where I can troubleshoot around that would be great.

I am stumped with the above so any help would be greatly appreciated. Please let me know if any more information is needed.

Cheers

Shaun

P.s This is my first time asking a question on StackExchange so please let me know if my question could have been clearer and/or more helpful.

Answer 1

I had some problems with Sitecore forms submit when Ajax was enabled (not submit duplication though). The solution in was to edit: \Views\FormBuilder\Form.cshtml and add @Html.RenderFormStyles() above form definition and @Html.RenderFormScripts() below form definition like so:

@Html.RenderFormStyles()

@{
    using (Html.BeginRenderRouteForm(Model, IsPost))
    {
        @Html.AntiForgeryToken()
        @Html.Hidden(AttributeNames.FormItemId, Model.ItemId)
        @Html.ValidationSummary(true)
        @Html.RenderFields(Model)
        <input type="hidden" data-sc-fxb-condition value='@Html.RenderConditions(Model)' />
    }
}

@Html.RenderFormScripts()

Answer 2

Please check, how many times the forms scripts are getting loaded. We were having same scenario for ajax enabled checkbox and after checking the html by inspecting, the script reference was twice.