Thanks for posting about this. Unfortunately this is a known limitation of the slider component.
Currently it’s 100% compatible with the CMS so it has that glitch you mentioned where a ghost slide exists. You’ll find there are a few workarounds for this when searching around the forums, but here’s one that should work for your use case: Ghost / Blank Slides When Using CMS Dynamic Images and Inputs
We hope to make the slider fully dynamic in nature in the future, but I don’t have an exact time frame for that.
Hope the workaround helps in the mean time! 