The filter looked like it was rushed being put together and the quality looks cheap. I actually had to buy another filter a week later from the company that had the original filter. They sold me 2 for the price of your cheap filter. Their quality was so much better. I have never had a problem with your filters so I was very disappointed.
The filters seem to be good overall, but I don't think there is any quality control when filling orders. 1/6 of my filters had the spacing so bad that I don't think I'll use it out of concern the airflow will be restricted.