Content not aligning to centre in mobile view

I have a slider on my site with the content set to be horizontally centrally aligned. When viewed in preview mode it works perfectly on all devices with the text in the middle of the slider. However, when published the content goes to the top of the slider on mobile landscape/portrait mode (desktop and tablet works fine).

Any idea why this might be happening and how I can get around this?

How it appears in preview mode:

How it appears when published:

Here is my site Read-Only: