Got my 150 mile N aligned

Have had the car for 3 days noticed when just cruising around town off throttle it was drifting off left. I know a guy with an alignment shop so I had him check it out. He checked alignment everything was spot on. So he swapped the front driver side tire to the front passenger side and took it for a spin and it was now drifting right. We checked tire pressure everything was good. So we went ahead and threw the tire that’s causing the pull the the driver side rear and it solved the issue. Drive straight as an arrow after that. He says he’s seen this a couple times now with brand new tires. But glad I got it resolved !