Is this a huge problem? The house frame is about 2" off the slab along the north side. On the other sides of the home it varies by 1", but not in as many places.
If I were a buyer I would beware.
Why is the house frame not firmly on the foundation?
2" off the slab is more than half the width of the 2x4 base of a wall.
I would start by evaluating the north wall section in several ways. First of all use a nylon string (such as a masons line or a chalk line). Stretch this along the outside edge of the slab to see of the original slab was poured straight all across the area where the wall overhangs the edge. Secondly repeat this test along the lower edge of the wall (outside) to see if the base of the wall runs a true straight line. And then third attempt to run the same test along the upper side of the wall (also outside). If the house is multi-story do this wall test along a point where the wall meets the second story. These three tests will quickly help you to determine if the overall structure was built correctly or not. There is always the possibility the the slab was built in a shoddy way and not straight from the beginning.
If by chance the walls are not actually sitting on a concrete slab that forms the floors on the inside of the house then there is a possibility of another serious problem going on. If the house wall is straight along the bottom edge and not matching to the foundation wall it may be that the foundation wall has tipped due to movement of the soil. If so then this needs to be looked into carefully.
Checking if various lines are straight may help explain why there's an overhang, but the question remains: Is this a huge problem? I don't know if we can fully answer this, as the devil's in the details. Are there additional floors? Is this in snow country, if so what's the snow load? What are the wind and seismic concerns? Is the wall 2" off a bearing wall?
The bottom plate of the wall must have adequate bearing area on the concrete or the vertical studs could actually crush the fibers of the bottom plate. It may not be an issue for regular studs but beam supports are a big concern. Even good sized openings in the wall could be an issue.
Then there's the lateral concerns from wind and possibly seismic. The bolts or whatever anchors are used are probably all misaligned, with very decreased edge distances, significantly reducing the ultimate strength of the assembly.
What all this means is there is cause for concern, but depending on the design loads involved and their locations, it may not be a problem, or could be a huge problem. Without a detailed study, it will be very difficult to say.
I am going to go with the most logical explanation of what is causing this and I could be wrong.
Most commonly this is an error in the foundation pour. Not only an error in foundation pour but then the lead contractor didn't notice it was poured wrong until his crew got a good way into constructing.
There is a really good chance that the walls are built modular (either on site or not) per architect's drawings (think lego steps). They start noticing things are off so start shifting the walls so that the house fits.
Is this is problem? Well I remember an architect that I had years back explaining to me that he likes a 1/4" hang on the walls. He went into enormous detail and I wasn't listening much but to sum it up (in my head) it was to prevent exposure gaps and so the siding sat better on the edges. (Remember most concrete, even using forms, isn't straight for long walls, so without an overhang you probably are under in spots)
Well I still haven't answered the question! I think there are two main things that answer this. #1 Are the outer walls 2x6 construction. If not I have some major major issues with the overhang at 2" for 2x4 framing. A foundation issue, soil issue or earthquake and your house could collapse.
And #2 Did they consult with an engineer or architect during the build? If the crew just "hid" this problem, I would not trust it at all. So how do you know? You start with the city. You ask them for the papers on who signed off on the construction of the house. You tell them about the overhang and see if that is documented. If it is documented it was OK'ed by engineer or local inspector. If it was not documented the local inspector will need to start working. He will need to figure out who built the house and contact them - this is a huge f-up by inspector if not documented.
Personally, unless I see that the crew did their due diligence about getting the overhang OK'ed I find this a huge huge red flag on the house. If they hid this what else are they hiding? Usually when one thing this shoddy is done it is a pattern. This could be a great house with little to no problems - but as a buyer I would stay away for this one glaring issue. I still flip a house every year or two and I wouldn't touch this as a flipper. (I want the houses I flip to turn out good for new buyers and I don't want to see this raised during a home inspection)