Index: /branches/2dbias/ppImage/src/ppImageDetrendReadout.c
===================================================================
--- /branches/2dbias/ppImage/src/ppImageDetrendReadout.c	(revision 42717)
+++ /branches/2dbias/ppImage/src/ppImageDetrendReadout.c	(revision 42718)
@@ -153,4 +153,13 @@
                 ESCAPE(false, "Unable to determine whether 2D Overscan subtraction should be applied.");
             }
+            // set doTwoDOverscan to False if the cell background is larger than 500 ADU or smaller than zero (peculiar)
+            if (doTwoDOverscan)
+            {
+                float backest = psMetadataLookupF32(NULL, input->parent->concepts, "CELL.BACKEST");
+                if (!isfinite(backest) || backest > 500 || backest < 0)
+                {
+                    doTwoDOverscan = false;
+                }
+            }
         }
         if (!pmOverscanSubtract(input, options->overscan, doTwoDOverscan))