Could just be "just" an out of plumb interior wall, or could be this:

Framers go home. Something shifts. No one checks for plumb before the sheeting goes on the next day. Entire structure is out of plum on two opposite sides.

No one notices until they start to build out the interior - only by this point the roof is on, windows, and exterior doors installed, siding is on, etc... so the crew doing the interior attempts to shim things right.

All kinds of problems can then result - for example I once saw a FG shower stall which cracked top to bottom the first time it was used because it backed up to out-of-plumb exterior wall slanting inwards; the sub- floor below the stall was level but the front face of side-wall framing to which the front of the one-piece shower was screwed was out of plumb, the installer's "solution" was to attempted to shim under the floor of the shower - but the back end of the base was hanging 7/8" off the floor.

In such a case *everything* which depends on a plumb wall is suspect - look carefully at kitchen cabinet installations, tub and tub showers, doorways, etc., some areas may be "fixed", some not.