Iron-router this.params.query is wrong in IE9

I have a problem with IE9 and iron-router “query” parameter, in IE9 only.
One time I have good Object parameter but one time it`s wrong and I have a string.

It`s code from iron-router (data for Template)

data: function(){
var templateData = {

  filter_params: this.params.query

return templateData;


Any ideas?