diff --git a/.gitea/workflows/build.yml b/.gitea/workflows/build.yml
index 1c990d5..585d8b4 100644
--- a/.gitea/workflows/build.yml
+++ b/.gitea/workflows/build.yml
@@ -80,7 +80,7 @@ jobs:
         uses: actions/cache@v4
         with:
           path: .deps
-          key: obs-deps-${{ runner.os }}-${{ hashFiles('cmake/macos/buildspec.cmake', 'cmake/common/buildspec_common.cmake', 'buildspec.json') }}
+          key: obs-deps-v2-${{ runner.os }}-${{ hashFiles('cmake/macos/buildspec.cmake', 'cmake/common/buildspec_common.cmake', 'buildspec.json') }}
 
       - name: Configure, build, test, verify
         run: .gitea/scripts/macos-build.sh
@@ -147,10 +147,22 @@ jobs:
         # needed: cmake/windows/buildspec.cmake's own download logic is
         # already idempotent, it just never gets the chance because .deps/
         # lives inside the checkout and is wiped by every fresh clone.
+        #
+        # The `v2` in the key: actions/cache never overwrites an existing
+        # key -- once a key has a saved entry, every later job's save step is
+        # skipped as a no-op, cache hit or not. The very first job ever
+        # to populate this cache did so BEFORE the "Drop non-relocatable OBS
+        # build tree" step below existed, so its save included the bad
+        # build_x86 directory -- and because saves under an existing key are
+        # permanently skipped, every run after that kept restoring that same
+        # bad entry forever, not "one more transitional run" as it looked at
+        # the time. Bumping the key is what actually forces a fresh save;
+        # bump it again (v3, ...) if this cache is ever found to be stale in
+        # a way a workflow change alone can't fix.
         uses: actions/cache@v4
         with:
           path: .deps
-          key: obs-deps-${{ runner.os }}-${{ hashFiles('cmake/windows/buildspec.cmake', 'cmake/common/buildspec_common.cmake', 'buildspec.json') }}
+          key: obs-deps-v2-${{ runner.os }}-${{ hashFiles('cmake/windows/buildspec.cmake', 'cmake/common/buildspec_common.cmake', 'buildspec.json') }}
 
       - name: Configure, build, test, verify
         # Windows PowerShell (powershell.exe), not PowerShell Core (pwsh) --