text fade not working in some instances – Safari – IOS

Hi. I have a problem with some pages on a live site. The issue concerns two types of page viewing in Mac Safari Version 6.2.8 (8537.85.17.9.1) and IOS Safari.

The text in the testimonials part at the bottom of the page displays the text too thin because the ‘fade-in’ fails.

https://www.jeffamos.co.uk/treatment/amalgam-removal-tooth-coloured-fillings/

This fade in works in other areas of the site but not in the page link above, and not in the case studies page. Regarding the case studies green text box and the link bar above.

The developers say they can’t replicate this a therefore are unable to advise, other than ‘find another solution’

The items work perfectly in the treatments page, but if I add a carousel or post cycle it fails. code below.
https://www.jeffamos.co.uk/treatment/

[content_box]
[row]
[span12]
[lazy_load_box effect=”fade” speed=”800″ delay=”200″]
[carousel_owl title=”case studies” post_type=”portfolio” categories=”fillings” posts_count=”50″ visibility_items=”3″ thumb=”yes” thumb_width=”533″ thumb_height=”300″ date=”no” author=”no” comments=”no” display_navs=”yes” display_pagination=”yes” custom_class=”center”]
[/lazy_load_box]
[/span12]
[/row]
[/content_box]
[cherry_parallax image=”parallax_51.jpg” speed=”normal” invert=”false” custom_class=”extra”]

patient testimonials

[row]
[span12]
[post_cycle num=”50″ meta=”false” thumb=”false” category=”testimonials-amalgam-removal-tooth-coloured-fillings” excerpt_count=”120″ effect=”slide” pagination=”true” navigation=”false” custom_class=”extra”]
[/span12]
[/row]
[/cherry_parallax]

Is this likely to be a CSS issue or a template problem? Some advise would be really helpful on how diagnose and or repair?

Best wishes Nick Allen.
WordPress 4.5.3 running theme53016 theme.