Working with the carousel widget with a Jive cloud customer and we noticed when adding or removing a slide it adds or removes from every other carousel in the instance regardless of what Jive space it is located. After troubleshooting various conditions it occurred to me the carousel was part of a "Copied" space. The original space was being copied to replicate the layout in other spaces. Even though the new spaces didn't show any slides any new slides replaced the all carousels that had the copied space.
So basically, the copied space which contained carousel widget always used the most updated slides. The work around is to copy the space but use a new carousel widget and remove the widget that was copied.
I ran into this problem this week in my company's 6.x.x community. I opened a support case with Jive and they confirmed that this is a known issue that has been corrected in Jive 7.
This is the issue number they referenced in the case: