concave continues loop issue with 4 cells

I have only 4 blocks in my carousel and for some reason it's not working properly. It does if I duplicate them, with 8 items it works perfectly. What do I need to do?

Reproduce the Bee3D carousel with four blocks, then compare it with the reported working case using eight items. Identify the slider entry point involved in the looping behavior and confirm the fix by verifying that four blocks continue looping without requiring duplicates.

Written by the indexing model from the issue text.