Wrong render parameters on multiple renders

I am having a problem with a render I am creating in Sitecore 8 Update 3 using MVC with Glass Mapper v4.

I have a render Feature Promo

that has a render parameter template Feature Promo Parameters

that defines a droplist field with a name Align

with possible values Left

and Right

.

When in experience editor and in preview mode the render is displayed correctly, and when debugged RenderingContext.Current["Parameters"]

contains Align=Left

or Align=Right

respectively, and Glass displays this value correctly in my POCO.

However, when in web mode the first render has Align=Left

as its parameter, all subsequent renderings of the same type are Align

irrelevant.

Checking the XML layout in the web database via Sitecore Rocks, I can see the parameters are correct:

<r p:p="1" xmlns:p="p" xmlns:s="s">
    <d id="{FE5D7FDF-89C0-4D99-9AA3-B5FBD009C9F3}">
        <r p:before="r[@uid='{CAE5DB0F-1971-4931-939B-9F7DB14AF0F8}']" 
           s:ds="{F63266A5-CC62-4915-9D89-CB01C7A0D05A}" 
           s:id="{6BA52384-D976-499D-8A0D-7F729EB4376B}" 
           s:par="Align=Left" s:ph="main" 
           uid="{4CBD0824-D232-46F9-8763-295D3B493A4F}"/>
        <r p:before="r[@uid='{12A7C72A-1821-4F8D-9A87-745604BE5106}']" 
           s:ds="{C50C7579-3680-46C3-93B2-9429EB9E0100}" 
           s:id="{6BA52384-D976-499D-8A0D-7F729EB4376B}" 
           s:par="Align=Right" s:ph="main" 
           uid="{CAE5DB0F-1971-4931-939B-9F7DB14AF0F8}"/>
        <r p:before="*[1=2]" uid="{12A7C72A-1821-4F8D-9A87-745604BE5106}"/>
    </d>
</r>

      

        
        
        
      

    

No matter what I do, the second (and any subsequent renderings of the same type) does not receive the specified parameter value.

The rendering code looks like this:

@model Promo
@{
    var settings = Html.Glass().GetRenderingParameters<FeaturePromoParameters>();
    var alignment = "feature-promo-style-a";
    if (settings != null && settings.Align.EqualsText("Right")) {
        alignment = "feature-promo-style-b";
    }
}

<div class="feature-promo @alignment">
    <div class="layout layout-a">
         <div class="region region-a">
            <div class="region-inner">
                <div class="feature-promo-image-container">
                    @Html.Glass().Editable(m => m.Image)
                </div>
                <div class="block block-size-b feature-promo-text">
                    @if (Html.Glass().IsInEditingMode || !Model.PreTitle.IsEmptyOrNull()) {
                        <div class="pre-title">@Html.Glass().Editable(m => m.PreTitle)</div>
                    }
                    @if (Html.Glass().IsInEditingMode || !Model.Title.IsEmptyOrNull()) {
                        <h2 class="h3 color-a">@Html.Glass().Editable(m => m.Title)</h2>
                    }
                    @Html.Glass().Editable(m => m.Body)
                </div>
            </div>
        </div>
    </div>
</div>

      

        
        
        
      

    

Can someone please advise what I am doing wrong or if I found a random error?

Update for Marek Musielak:

OK, now it's only once hitting the breakpoint - and has uid first rendering on the page: {4CBD0824-D232-46F9-8763-295D3B493A4F}

. Could this turn out to be something to do with dynamic placeholders?

RenderingContext.CurrentOrNull.Rendering["Parameters"] = "Align=Left"