It could just be adjusted a little too far down. Try loosening the two bolts and tapping it up slightly.
That could cause it to latch around town fine and then not so great on the highway eh? You might be on to something there, the car apparently caught a loose wheel and tire smack in the middle of the grill years back on the highway, so maybe once everything was straight it was not quite adjusted right.
I never had the issue last year, and there were a few times I was in a hurry and holding 90mph with the thing LOL (Late for a wedding out of town)
I never worried about the latch on the Aspen before. They are quite strong when they are proper. After the Aspen started running 130mph, the hood front corners have started bending up on the hood, but no latch problems
-Kenny