I just replaced the line from the main water to the tank and I also replaced the fill valve assembly. After replacing I noticed the toilet now runs every few hours or so. I checked all connections and there are no leaks anywhere and I also put some food coloring into the tank to see if it was leaking through the flapper and it wasn't. The bowl was clean after a few hours so I am wondering...

Where else could the water be going that is causing it to fill the tank? It happens every few hours and just for a few seconds at a time.

I installed a fluidmaster fill valve assembly.

Several things come to mind1- the tank level may be set too high. It should be one half inch below the top of the white overflow tube. When the fill valve shuts off.
2- Some trash might have found its up to the seal where it is now blocking the opening in the seal allowing water to seep out and flow into the white overflow tube.
In that case, shut the water off open up the valve and then turn the water back on to flush out any remaining debris. Let me know what you find. Good luck, Tom

More accurate way of checking for a leaking flapper.

Remove tank lid. Hold down float until water runs into overflow. Turn off stop valve. Come back later to check water level. Causing the water to run into over flow is most accurate way of marking water level. More accurate than a laser.

Also make sure that no water is flowing into overflow pipe from refill tube after you let the float up. If it does, it means you have the refill tube down in the overflow pipe, below the water level, and water is being siphoned from the tank into the overflow.

You are getting good advice from these two experts, I am going with the fill level is set to high.