Bundle boxes wont open (js error)

I am unable to open the bundle options on the product page. When I click on the boxes nothing happens. They do not open.

When I check the console there is a js error:

Uncaught Error: Option ‘ajax’ is not allowed for Select2 when attached to a <select> element. at String.<anonymous> (select2.min.js:21:22578) at Function.each (jquery.min.js:2:3003) at d.prepareOpts (select2.min.js:21:22459) at d.prepareOpts (select2.min.js:22:17948) at d.init (select2.min.js:21:17973) at HTMLSelectElement.<anonymous> (select2.min.js:22:30935) at Function.each (jquery.min.js:2:3003) at s.fn.init.each (jquery.min.js:2:1481) at s.fn.init.a.fn.select2 (select2.min.js:22:30623) at bopobb_select2_init (bopo-product.min.js:1:9502)