SSRS Chart Pattern style issue when exporting to PDF

Hi All,

In a bar chart, we are using the LargeCheckerBoard as the pattern style in series properties > fill. It is showing correctly on the browser but if we export to PDF, this style(checks) are getting small and different from what shown on the browser. Could you please help me on this, is there any workaround for this? 

Using SSRS 2014

Thank you.