The code of jlaccordion.html.twig includes in line 240 the class jl-margin-remove-first-child:
<div class="jl-accordion-content jl-margin-remove-first-child">
In my experience, this overrides any margin settings that can be made from the particle (e.g. in Style tab > Content Settings > Margin Top ).
Considering that the contents within each accordion are unique, I don’t understand the reason for this setting – unless there is another function I’m not aware of.
I propose to remove this code. Thanks!