Server Resource Usage Surge

Hi,

We have a site hosted with WPEngine and are seeing a sudden surge in resource usage of our site. Everything was fine up until 9 days ago and no development has been carried out. The dev team @ WPE have said that it’s to do with the Favorites plugin making ~140 calls per minute to wp admin ajax.

The plugin is used to allow anonymous users to select favorites, which are stored via Cookies, and are then retrieved at a later stage.

Are there any reasons why this might have started happening? Any recommendations you can think of would be super helpful.

Many thanks