Testimonial arrow showing different color

Hi,

Firstly, thank you for creating this theme and the plugin.

I have a weird issue with the testimonials block, where the arrow is a different color on the frontend, however looks fine when editing the page

editing page: https://i.imgur.com/qiZb5lO.jpg

frontend: https://i.imgur.com/0rAcoSo.jpg

link: https://heidi.pleskwp.tk/

Please help, thank you in advance and have a great day!

yours sincerely,

Nick

The page I need help with: [log in to see the link]