Hi Daniel,
I guess the issue is related to Altium Designer 16, Smart Component Placement feature which provides 3 placement options (Ignore Obstacles , Push Obstacles, Avoid Obstacles).
For more details, please refer to the link below:
http://techdocs.altium.com/display/ADOH/((Smart+Component+Placement))_AD
If you are not using some other version of Altium Designer, please let me know the version.
Regards,
Satyan Raj