Hey Dennis,

It seems like this custom css code causing the issue -> JoomlaFolder/templates/cd_propertyplan/css/custom.css

/*Payplans plans subscribe button*/

.btn {

	margin-top: 30px;

}

To fix this, you have to define back the payplans subscribe button css class name so it will not conflict with other button who call .btn

After you remove the css code, you have to disable this plugin first -> System - JCH Optimize Pro then clear all the joomla cache and see is it work fine, if yes, only enable back the plugin.

Hope this help.