Detector rails still triggering junction changes prematurely

Detector rails still trigger junction changes before a cart actually hits the detector rail. I believe this may be because the "hitbox" for triggering cart interactions may be slightly too large, and thus triggering the detector rail when it is diagonal to it.
RTR
D

R=Rail
T=Turn
D detector rail

When the cart is in the upper left or upper right, the T will flip before it gets to the D.