MaxButton: Links Not Working

I’m running both the latest version of MaxButtons and WordPress. Unfortunately, all of my buttons seem to be broken. The links have somehow changed and are now all incorrect.

The URL that I’m using for two different buttons contains an equals sign. When I go in to edit the buttons, the link there is correct. However, when they are added to my page, the link changes. The equals sign becomes %3D instead.

For example, the correct link in the button editor shows: add-to-cart=123
When added to a page, the link breaks and shows: add-to-cart%3D123

Any idea what could be causing this or how to fix it? Fortunately, I had a customer who was kind enough to let me know. (Not a great issue to have in the middle of a product launch!)