How to reproduce:
1. Create new project
2. Create Cube in Hierarchy
3. Make it a prefab by dragging it to Project tab
4. Drag Cube prefab into Scene and keep holding the mouse button
5. Click Alt key (Option on Mac) several times

Expected result: Object stays in mouse position
Actual result: Object moves away in random direction from mouse position while Alt key is held

Reproduced with: 2021.2.3f1, 2022.1.0a15
Does not reproduce with: 2020.3.21f1 (Scene tools overlay was not a part of Scene tab)

Notes: Issue is reproducible with Mac and Linux (CentOS 7), does not reproduce with Windows