Fulltextsearch 1.3.6 api.search is not a function in browser console

Hello, I am using the plugin in version 1.3.6 and I am getting this error message (api.search is not a function) in the browser console when I try to use the search bar. However, the plugin is working divinely if you enter its search page.

which browser are you using ?

I’m using a Google Chrome 78