Hi Roy,
Thanks so much for your report, and welcome to the forum!
The problem has already been reported by another user:
It鈥檚 a splidejs bug on which we already created a report on: Vertical slider with fade only shows first slide 路 Issue #1095 路 Splidejs/splide 路 GitHub
I鈥檒l close this thread accordingly. We鈥檒l update the original thread as soon as we鈥檝e fixed the issue.
Best regards,
timmse