Occasionally circumstances in the interorder fluxes lead to solutions that are slightly unstable, producing wiggles in an interpolated region that go beyond the flux range of sampled pixels at the two spatial ends of the camera. Such occurrences may be caused by abnormal conditions affecting the image (eg., target-ring glow, cosmic ray hits, LWR flare, and flux down-turns at camera edge). A series of eight ``pathology tests'' has been added to BCKGRD to protect against blind solutions at the end of Pass 1 which do not agree with simple and often correct interpolations (see Appendix A for full details). These checks generally rely on a comparison of fluxes at two or more pixels along the swath or on a ratio of smoothed flux ranges. The rms statistic computed from local raw background fluxes is a convenient unit of measure for flux ranges because it does not rely upon source brightness, exposure time, or an arbitrary flux level. In most cases a failure of a solution in a pathology test causes either the PSF information not to be used in Pass 1, the degree of the polynomial fit to the interorder data to be reduced, or both. Lowering the fitting degree has the effect of removing extra wiggles in the solution; however, the degree of the Chebyshev fit is never reduced below 3. In those cases where superfluous wiggles in the IOR region persist stubbornly after a few trials, a simple linear interpolation is adopted between ``good'' regions. This may occur for spatial positions toward the short-wavelength (spatial) end of the IOR for certain swaths having reliable background samplings at the target edge. These tests are used only for continuum source images in Pass 1. Therefore, the final output background vectors from Pass 2 are still guaranteed to be pure continuous Chebyshev functions.