Why doesn't my HORIZONTAL ANIMATION work on all pictures in my Slide Show Full Gallery

Hello,

I have a FULL SLIDE SHOW on my main page with HORIZONTAL ANIMATION turned on.  However, not all pictures have the horizontal animation transition.  Some images just jump to the next slide.  Is there a fix for this?  Thank you so much for your help.

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https://plums-denim-9r92.squarespace.com/config/

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KOO

Thank you,

Natalee