Thank you for contacting us.
I am sorry that your macrons are not displaying properly in Internet Explorer. BoldGrid uses the standard Google Fonts library and I suggest reaching out to them for support on what can be done to make the fonts display properly in Internet Explorer. Once they are able to provide you with a solution we can help you get it implemented properly on your website.
Please let us know if you have any other questions as well and we will do everything we can to help.