diff --git a/task/buildah-oci-ta/0.1/buildah-oci-ta.yaml b/task/buildah-oci-ta/0.1/buildah-oci-ta.yaml
index 8009ff15c8..830eeb2081 100644
--- a/task/buildah-oci-ta/0.1/buildah-oci-ta.yaml
+++ b/task/buildah-oci-ta/0.1/buildah-oci-ta.yaml
@@ -303,7 +303,12 @@ spec:
           cp -r "/var/workdir/cachi2" /tmp/
           chmod -R go+rwX /tmp/cachi2
           VOLUME_MOUNTS="--volume /tmp/cachi2:/cachi2"
-          sed -i 's|^\s*run |RUN . /cachi2/cachi2.env \&\& \\\n    |i' "$dockerfile_path"
+          # Read in the whole file, then for each RUN ... line insert the cachi2.env command
+          # *after* any options like --mount.
+          sed -E -i \
+              -e 'H;1h;$!d;x' \
+              -e 's@^\s*(run((\s|\\\n)+-\S+)*(\s|\\\n)+)@\1. /cachi2/cachi2.env \&\& \\\n    @igM'
+              "$dockerfile_path"
           echo "Prefetched content will be made available"
 
           prefetched_repo_for_my_arch="/tmp/cachi2/output/deps/rpm/$(uname -m)/repos.d/cachi2.repo"
diff --git a/task/buildah-remote-oci-ta/0.1/buildah-remote-oci-ta.yaml b/task/buildah-remote-oci-ta/0.1/buildah-remote-oci-ta.yaml
index dd1a40ec47..1b9d7e75f8 100644
--- a/task/buildah-remote-oci-ta/0.1/buildah-remote-oci-ta.yaml
+++ b/task/buildah-remote-oci-ta/0.1/buildah-remote-oci-ta.yaml
@@ -320,7 +320,12 @@ spec:
         cp -r "/var/workdir/cachi2" /tmp/
         chmod -R go+rwX /tmp/cachi2
         VOLUME_MOUNTS="--volume /tmp/cachi2:/cachi2"
-        sed -i 's|^\s*run |RUN . /cachi2/cachi2.env \&\& \\\n    |i' "$dockerfile_path"
+        # Read in the whole file, then for each RUN ... line insert the cachi2.env command
+        # *after* any options like --mount.
+        sed -E -i \
+            -e 'H;1h;$!d;x' \
+            -e 's@^\s*(run((\s|\\\n)+-\S+)*(\s|\\\n)+)@\1. /cachi2/cachi2.env \&\& \\\n    @igM'
+            "$dockerfile_path"
         echo "Prefetched content will be made available"
 
         prefetched_repo_for_my_arch="/tmp/cachi2/output/deps/rpm/$(uname -m)/repos.d/cachi2.repo"
diff --git a/task/buildah-remote/0.1/buildah-remote.yaml b/task/buildah-remote/0.1/buildah-remote.yaml
index 316c358302..e8f8c1484b 100644
--- a/task/buildah-remote/0.1/buildah-remote.yaml
+++ b/task/buildah-remote/0.1/buildah-remote.yaml
@@ -312,7 +312,12 @@ spec:
         cp -r "$(workspaces.source.path)/cachi2" /tmp/
         chmod -R go+rwX /tmp/cachi2
         VOLUME_MOUNTS="--volume /tmp/cachi2:/cachi2"
-        sed -i 's|^\s*run |RUN . /cachi2/cachi2.env \&\& \\\n    |i' "$dockerfile_path"
+        # Read in the whole file, then for each RUN ... line insert the cachi2.env command
+        # *after* any options like --mount.
+        sed -E -i \
+            -e 'H;1h;$!d;x' \
+            -e 's@^\s*(run((\s|\\\n)+-\S+)*(\s|\\\n)+)@\1. /cachi2/cachi2.env \&\& \\\n    @igM'
+            "$dockerfile_path"
         echo "Prefetched content will be made available"
 
         prefetched_repo_for_my_arch="/tmp/cachi2/output/deps/rpm/$(uname -m)/repos.d/cachi2.repo"
diff --git a/task/buildah/0.1/buildah.yaml b/task/buildah/0.1/buildah.yaml
index 79d147cc8b..318bc0394f 100644
--- a/task/buildah/0.1/buildah.yaml
+++ b/task/buildah/0.1/buildah.yaml
@@ -257,7 +257,12 @@ spec:
         cp -r "$(workspaces.source.path)/cachi2" /tmp/
         chmod -R go+rwX /tmp/cachi2
         VOLUME_MOUNTS="--volume /tmp/cachi2:/cachi2"
-        sed -i 's|^\s*run |RUN . /cachi2/cachi2.env \&\& \\\n    |i' "$dockerfile_path"
+        # Read in the whole file, then for each RUN ... line insert the cachi2.env command
+        # *after* any options like --mount.
+        sed -E -i \
+            -e 'H;1h;$!d;x' \
+            -e 's@^\s*(run((\s|\\\n)+-\S+)*(\s|\\\n)+)@\1. /cachi2/cachi2.env \&\& \\\n    @igM'
+            "$dockerfile_path"
         echo "Prefetched content will be made available"
 
         prefetched_repo_for_my_arch="/tmp/cachi2/output/deps/rpm/$(uname -m)/repos.d/cachi2.repo"