Wrong nested GET arguments serialization results in validation errors

You can reproduce this error with HS taxonomy views and view with numeric field inside & between operator.

In this case the GET looks like "http://example.com/view-adress?field[min]=0&field[max]=123". HS taxonomy sends it's AJAX request to "http://example.com/view-adress?field=[object Class]", as it threats GET wrong (there are nested tree in $_GET array).

Instead of converting GET array into string in module, you should use drupal_query_string_encode() function, which will handle nested GETs properly.

Here's a working patch to fix this.