This is result of “auto-layout” of the Adalo’s engine. Such effects are quite frequent with “conditionally visible” elements, as Adalo doesn’t always manage to calculate item positions correctly with all these conditions.
I would recommend to have 2 groups (rectangle + content inside), one is for “occupied” slot and the other for “free” slot. Make them conditionally visible. Put one right above the other (like these 2 buttons on the screenshot - only one is visible at a time).
With some fine-tuning, you’ll get the result that these 2 groups will perfectly “replace” each other based on the condition.
Best regards, Victor.