Snap to Half Grid
By default, Roll20 snaps to the nearest corner.
This allows the snap to be the center of the grid or the nearest half grid.
Go to the Config Editor, to the Canvas Tab 📁 Click to enable (or disable) Snap to Half-Grid
Support/Suggested Use Guidance.
(this is a community-curated set of best practices / FAQ on the feature's support and solutions/workarounds.)