Avoid Obstacles - The component to be placed will be forced to avoid violation clearances between other components during placement.In this mode, components are identified by their selection boundary, which is the smallest possible rectangle that encloses all of the primitives in the component. Components in unions can be pushed and the location of components in the union may change, but the union will not break. Push Obstacles - The component to be placed will push other components away to provide compliance with clearances between components.These routines use the 3D body, if there is one, or the copper and silk primitives to identify an object's clearance. In this mode, the same component clearance checking routines seen in previous version of Altium Designer are used. Ignore Obstacles - Regular placement behavior, as seen in previous versions of Altium Designer.You can cycle through placement modes by pressing the R key during placement. Select the component to move, and press 'R', then you can put the component closer as you want.

Fond the problem!! it is not a issue, it is a new placement option.

Altium designer 20 move 3d body