I am going to add a YEAH, BUT
While some of these examples are indeed anomalies that just happen, still others have to do with the boundary being the route of the river at a past date. There places along the lower Mississippi where the boundary is nearly 10 miles from the current river channel to the state line. I cannot think of any that have roads through the oxbow peninsulas, but if there were, it would be really confusing. Technically the US-82 bridge at Greenville both landings are in Arkansas. The approach on the Mississippi side is partly in Arkansas, but the state line falls before east bank levee.
The Arkansas / Texas border at Index on US-71 is one of these. The highway signs don't help it any.
The Northbound Bridge leaves Miller County Arkansas and arrives in Little River County Arkansas.
The Southbound Bridge Leaves Little River County Arkansas and arrives in Bowie County TX.
Then again, All the Texas Bridges on the Red River TECHNICALLY leave and arrive in the other state because Technically the other state controls to the high water mark.