I have not built the F, but I have built several of their Panther series. Yes, there are several fit problems. One problem with the diecast hull is that the upper and lower hulls do not fit well together. You will need to chip off the primer paint where the hull parts meet and even file off some metal especially around the front of the hull. If not, you will get a large gap between the upper and lower hulls at the point of the front of the hull.
Test fit this and make the adjustments before beginning assembly.
The tracks are also too tight. It is a problem since the sprocket and idler mounts are molded metal on the lower hull. If it was plastic, you could cut off one or the other and move it inside a few millimeters. You can cheat by elongating the mounting holes on the inside of the idler wheels. This will loosen up the tracks just a little bit.
A more optimal solution would be to grind off the idler mounting points, then drill a hole through each side of the metal hull located slightly forward and place a piece of styrene rod or metal axle through the holes. This would give you enough slack to make the vinyl tracks sag properly. This would also be more difficult to do than the easy method above.