MC-105820 commands which modify blocks or get data from them use the block grid instead of the position of the command executor. This causes values from 0 up to 1 (exclusive) to select the block the command executer is in, while -1 to 0 (exclusive) selects the block in the negative direction. This behavior was stated as WAI by [Mojang] Grum (Erik Broes). The problem is that as these commands allow decimal values you would expect them to be based on the position of the command executor.
To make it clearer that this is not how it works, it might be more intuitive to allow only integers as coordinates (relative as well).
- /stats block
- /replaceitem block