Electronic – Altium connection to multiple devices with same pad-to-pad trace len for each path

It's worth noting that the mouse-snap actually uses the autorouter to some extent.

Depending on the routing mode you have enabled, it will behave differently. Shift+ R while in the interactive routing mode (e.g. placing traces) changes the routing mode.

Anyways, if you want to change the orthogonality of the traces as you're routing, you just press the space, and it should try the other angle (_{note that some routing modes are more responsive to hitting space then others in the more recent versions, particularly if you have pin swapping turned on}).

Fundamentally, polygons are evaluated separately in the DRC system.

Traces are traces, and polygons are polygons. The DRC system for checking trace width runs effectively with the polygons all shelved.

Realistically, when would you ever want to have traces that violate the design rules? If they're embedded in a polygon to the point where their width is irrelevant, you can delete them. If they're not embedded in a polygon to the point that their width is irrelevant, their width is relevant.

You're doing something that does not make sense, and the DRC doesn't account for it because there is no reason to do what you are doing.