Plugin conflict occurs under WP 4.2.4

Since upgrading WP to 4.2.4 IvyCat Testimonials has been conflicting with the Page Builder by SiteOrigin plugin. With both plugins activated my whole site whitescreens, where they were working together (and the site works fine with either plugin activated). I have tried rolling back both plugins to earlier versions, but there is still an issue.

I have brought this to Site Origin’s attention already, as I initially thought that it was just their plugin that was broken. Having discovered that there is a conflict I thought it best to make you guys aware too.

https://www.ads-software.com/plugins/ivycat-ajax-testimonials/