Inconsistent appearance or behavior?
Symptom
A testimonial view does not look right the first time you view the page – for example, it does not seem to have any style, the slideshow has not started, or the pagination is missing – but does work when you refresh the page.
Possible cause
Your site may be using Ajax page loading – also known as page animations, transition effects or Pjax (pushState Ajax) – provided by your theme or another plugin.
Try
Go to wp-admin Testimonials Settings Compatibility tab and set Ajax Page Loading to General.