Blender 2.92 (and possibly 2.93.5)

Windows 7-64

Alt middle mouse button causes timeline slider to move, even when mouse pointer is not hovering over the timeline. To keep things consistent, the timeline slider should not move when using Alt MMB in the main viewport.

For example, Ctrl MMB doesn't have this problem.

Note: I was unable to test this in Blender 2.93.5 in Windows since my workstations are Windows 7-64 and will remain that way. The latest version of Blender dumped support for pre-Windows 8 builds; a practice that I formerly believed was reserved for the elitist big software giants. Disappointing and unnecessary.