diff --git a/MobileGL/MG_Impl/Pipe/TextureEmit.h b/MobileGL/MG_Impl/Pipe/TextureEmit.h
index 4858d698..cc208ada 100644
--- a/MobileGL/MG_Impl/Pipe/TextureEmit.h
+++ b/MobileGL/MG_Impl/Pipe/TextureEmit.h
@@ -1479,11 +1479,15 @@ namespace MobileGL::MG_Pipe {
             // hold GPU writes (and otherwise it re-applies the storage's box-or-rects choice
             // itself, so the Mali job count is the server's call as before).
             //
-            // 0 IS NOW THE WHOLE-LEVEL SPELLING ONLY: a footprint that is the whole level. Every
-            // other write carries its boxes, a single one included, so that the applier's
-            // accumulation (boxes union, lists concatenate, "0 regions" makes the entry box only)
-            // never widens two exact contributions into their union box. A footprint larger than
-            // one record may carry falls back to the storage's rect list - a COVER, stated once.
+            // 0 IS NOW THE WHOLE-LEVEL SPELLING - a footprint that is the whole level - with one
+            // exception (below). Every other write carries its boxes, a single one included, so the
+            // applier's accumulation (boxes union, lists concatenate, "0 regions" makes the entry
+            // box only) never widens two exact contributions into their union box. THE EXCEPTION:
+            // a footprint larger than one record may carry (kMGPipeMaxPendingUploadRegions) falls
+            // back to the storage's rect list - a COVER, stated once in the log - and when that list
+            // is withheld (0: its rects fill 3/4 of the union box) this 0 is a PARTIAL, INEXACT
+            // box. A reader that takes "box only" as "the client owns every texel of the box"
+            // (AdoptDriverLevelIntoShadow's covering-box rule) is exact everywhere but here.
             //
             // READ AS BOXES, ONCE, because both shapes below want them in that form: the
             // whole-level record converts each one straight back through MGPipeBuildSubRegion,
diff --git a/MobileGL/MG_Pipe/PipeApply.cpp b/MobileGL/MG_Pipe/PipeApply.cpp
index 54c0d06c..92cf5cb5 100644
--- a/MobileGL/MG_Pipe/PipeApply.cpp
+++ b/MobileGL/MG_Pipe/PipeApply.cpp
@@ -902,8 +902,12 @@ namespace MobileGL::MG_Pipe {
                 if (entry.UploadTarget != record.Target || entry.Level != record.Level) continue;
                 entry.UnionBox = UnionOfBoxes(entry.UnionBox, record.UnionBox);
                 if (record.RegionCount == 0 || entry.Regions.empty()) {
-                    // A whole-level contribution (the emitter's only box-only spelling since P11
-                    // M2) owns every texel of the level, so the entry is that box, exactly.
+                    // A whole-level contribution (the emitter's box-only spelling since P11 M2)
+                    // owns every texel of the level, so the entry is that box, exactly. The one
+                    // other box-only record is the emitter's oversize fallback (a footprint past
+                    // kMGPipeMaxPendingUploadRegions goes out as the storage's cover, which it
+                    // withholds as 0 at 3/4 of the box), a partial box spanning gaps - already
+                    // inexact, and logged once where it is emitted (TextureEmit.h).
                     entry.Regions.clear();
                     return true;
                 }