diff --git a/.gitea/workflows/docker-publish.yml b/.gitea/workflows/docker-publish.yml
index fa9b8ff..6257531 100644
--- a/.gitea/workflows/docker-publish.yml
+++ b/.gitea/workflows/docker-publish.yml
@@ -593,6 +593,28 @@ jobs:
           platforms: linux/amd64
           push: false
           load: true
+          # provenance: false is LOAD-BEARING, not hygiene. buildx writes a
+          # provenance attestation into the metadata it hands back, and that
+          # metadata embeds the ENTIRE Dockerfile as one base64 "data" field on a
+          # single line. build-push-action writes the metadata to $GITHUB_OUTPUT
+          # as a `name<<ghadelimiter_<uuid>` heredoc, and Gitea's act_runner
+          # truncates any single line at exactly 65536 chars — so once
+          # base64(Dockerfile.variant) crosses 64 KiB the closing delimiter is
+          # cut off and the runner fails the job with
+          #   invalid format delimiter 'ghadelimiter_...' not found before end of file
+          # and NO failing step: every step reports Success, the smoke suite
+          # reports "0 failed", and the job is red anyway.
+          # Measured: Dockerfile.variant was 42251 B at v1.9.4 (base64 56355,
+          # fine) and 50034 B at v1.10.1 (base64 66712, truncated to 65536) —
+          # the cap corresponds to a 49152 B Dockerfile, so the v1.10.0/v1.10.1
+          # comment growth crossed it by 882 B. v1.10.0 run 704 and v1.10.1
+          # run 707 both died here; in 704 it hid behind a stale clipboard
+          # assertion. Trimming comments would "fix" it until the next comment.
+          # These smoke images are built with load: true and thrown away, so the
+          # attestation has no consumer. The PUBLISHED images are built by raw
+          # `docker buildx build --push` in run: blocks, which never writes
+          # $GITHUB_OUTPUT metadata — so this changes nothing about what ships.
+          provenance: false
           tags: pi-devbox:smoke
           build-args: |
             BASE_IMAGE=${{ env.IMAGE }}:${{ needs.base-decide.outputs.base_tag }}
@@ -658,6 +680,28 @@ jobs:
           platforms: linux/amd64
           push: false
           load: true
+          # provenance: false is LOAD-BEARING, not hygiene. buildx writes a
+          # provenance attestation into the metadata it hands back, and that
+          # metadata embeds the ENTIRE Dockerfile as one base64 "data" field on a
+          # single line. build-push-action writes the metadata to $GITHUB_OUTPUT
+          # as a `name<<ghadelimiter_<uuid>` heredoc, and Gitea's act_runner
+          # truncates any single line at exactly 65536 chars — so once
+          # base64(Dockerfile.variant) crosses 64 KiB the closing delimiter is
+          # cut off and the runner fails the job with
+          #   invalid format delimiter 'ghadelimiter_...' not found before end of file
+          # and NO failing step: every step reports Success, the smoke suite
+          # reports "0 failed", and the job is red anyway.
+          # Measured: Dockerfile.variant was 42251 B at v1.9.4 (base64 56355,
+          # fine) and 50034 B at v1.10.1 (base64 66712, truncated to 65536) —
+          # the cap corresponds to a 49152 B Dockerfile, so the v1.10.0/v1.10.1
+          # comment growth crossed it by 882 B. v1.10.0 run 704 and v1.10.1
+          # run 707 both died here; in 704 it hid behind a stale clipboard
+          # assertion. Trimming comments would "fix" it until the next comment.
+          # These smoke images are built with load: true and thrown away, so the
+          # attestation has no consumer. The PUBLISHED images are built by raw
+          # `docker buildx build --push` in run: blocks, which never writes
+          # $GITHUB_OUTPUT metadata — so this changes nothing about what ships.
+          provenance: false
           tags: pi-devbox:smoke-studio
           build-args: |
             BASE_IMAGE=${{ env.IMAGE }}:${{ needs.base-decide.outputs.base_tag }}