Slight differences in tires or tire condition or tire pressure or the geometry of the bike will make the difference between the bike wanting to run wide (wanting to stand up and go straight), or be neutral, or wanting to fall in and feel like it is going to tuck the front end. Of course, the actions of the rider make the difference too, but If the bike is not doing what the rider wants, then something needs to be done.
A rider with track experience will pick this out in a second. A rider without track experience may not be able to explain what they feel, only that it's not right.
If the bike wants to fall in (steering feels nervous, steering feels unstable, "front end wants to tuck" check: Tire pressure too high, tires incorrect sizes for the rims, tires have a profile which is too triangular for what the bike wants, front ride height or preload too low, rear ride height or preload too high.
edit: If the bike in question is the one in the original poster's signature, "the bike" is not the problem (a late model Honda CBR600RR is fundamentally good), "something wrong with the bike" there is not enough information to exclude, "something wrong with the tires" who knows, "something wrong with the operator" maybe ...