asp-all-route-data are being appended with asp-route-param

[thedangler]

Hello,
I'm trying to create links for my page but some of the links rely on what is previously in the querysting.
I get what is in the current querystring like so:

    Dictionary<string, string> params = new Dictionary<string, string>();
    for (int i = 0; i < Context.Request.Query.Count; i++)
    {

        params.Add(Context.Request.Query.ElementAt(i).Key, Context.Request.Query.ElementAt(i).Value);
    }

When using asp-all-route-data="@params" that seems to generate the link with the current querystring.
and when I do <a asp-all-route-data="@params" asp-route-nextpage="2"> i get a new link with &nextpage=2.

The issue is, doing this actually adds nextpage=2 to params so every link on my page now contains &nextpage=2.

Forexample down in my page I want to have links to change the return size so I'm doing
<a asp-all-route-data="@param" asp-route-size="10"> <a asp-all-route-data="@param" asp-route-size="20"> <a asp-all-route-data="@param" asp-route-size="50">

I'm getting a link of
href="..&nextpage=2&size=10" href="..&nextpage=2&size=20" href="..&nextpage=2&size=50"

I expected
href="..&size=10" href="..&size=20" href="..&size=50"

I didn't expect nextpage to be added to the params list.

How do I get around this issue?

I do not want to manually have to type out each asp-route-param because I'm getting all those in a loop from the querystring I they change all the time based on a gridview filters I want to maintain.

Is this a bug?