reverse builds SALSA_CI_MMDEBSTRAP_EXTRA_ARGS works for unstable but not experimental

Compare this build which successful do a build with local apt repository for unstable:

https://salsa.debian.org/jas/golang-github-thediveo-enumflag/-/jobs/8698133

with this build that attempts to do the same but for experimental:

https://salsa.debian.org/jas/golang-github-sigstore-rekor-tiles/-/jobs/8716520

As you can see, it fails due to CA cert validation, however the --include=ca-certificates is present in both. Something about experimental appears to make it forget that parameter? Maybe the following command should have had that parameter inserted into it?

I: Creating chroot on-demand by running:
mmdebstrap --variant=buildd --arch=amd64 --skip=output/mknod --format=tar unstable - --setup-hook=echo "deb http://deb.debian.org/debian experimental main" > "$1"/etc/apt/sources.list.d/experimental.list

The error is:

Ign:2 https://salsa.debian.org/jas/golang-github-transparency-dev-tessera/-/jobs/8393690/artifacts/raw/aptly experimental InRelease
Ign:2 https://salsa.debian.org/jas/golang-github-transparency-dev-tessera/-/jobs/8393690/artifacts/raw/aptly experimental InRelease
Err:2 https://salsa.debian.org/jas/golang-github-transparency-dev-tessera/-/jobs/8393690/artifacts/raw/aptly experimental InRelease
  SSL connection failed: error:0A000086:SSL routines::certificate verify failed / Success [IP: 209.87.16.44 443]
Fetched 10.9 MB in 7s (1522 kB/s)
Reading package lists...
W: Failed to fetch https://salsa.debian.org/jas/golang-github-transparency-dev-tessera/-/jobs/8393690/artifacts/raw/aptly/dists/experimental/InRelease  SSL connection failed: error:0A000086:SSL routines::certificate verify failed / Success [IP: 209.87.16.44 443]
W: Some index files failed to download. They have been ignored, or old ones used instead.

which suggests that ca-certificates was not installed.