Altium interactive routing is always ignoring obstacles
As the OP is asking, I'm posting the comment as an answer, since this was the real problem.

The behavior the OP was experiencing was due to the fact that the clearance rule was violated even at the starting point. It appears that if the routing violates rules at the starting point the smart placing feature does not work, and as soon as the line is completed the online checker complains.

The user can notice this because the line he starts drawing can go even on nearby pins.

The way to solve this is simple: avoid violating rules at the very first point of the routing