Tire issues

kidkotic2001

I took my car to a Nissan dealer because my rear tire (driver side) was leaking air slow, I wanted them to repair the tire. I was called in after a while to the car bay, I was told that the tire could not be replaced because they had found 3 nails in the tire and it was also pretty worn out instead of buying the stock yokohoma tires 245/45 r18 95w (Which was 660 A piece) I took the opportunity to get two new ones from a different location.

I took it to a tire shop (Martin Tire) and bought two Toyo proxes4 245/45zr18 100W. Cheaper and the guy told me they were a little better than my stock tires. I really do not know if that is true. So I was driving home and there is a long straight way so I decided to punch it (like Usual) but as soon as I got to about 80MPH the car started to swerve. Never felt like that before, I got home and looked at tires made sure they were installed properly right tire on the right left on the left. I noticed that my rear driver side tire was butterflied in. So I took it to Nissan the next day I told them what I was experiencing and they told me it was an Alignment. I paid 90 bucks for one and the issue still there I got it back and did the same thing hit 80MPH and it felt the same way. I was able to hit 100MPH without any issue before it never felt like it was going to swerve.

Can anybody tell me if its the tires or something else? I am going to take it back to Nissan to see what else it could be but I wanted to see if anyone else has experienced this.