buildah: CI and f37 gating tests: failure in --runtime-flag test - maybe crun?

Impossible-to-debug failure in f37 gating tests:

not ok 696 run --runtime --runtime-flag
# (in test file /usr/share/buildah/test/system/run.bats, line 810)
#   `[ -n "$output" ]' failed
# /usr/share/buildah/test/system /var/str
# # [checking for: docker.io/library/alpine]
# # [restoring from cache: /var/tmp/buildah-image-cache.5515 / docker.io/library/alpine]
# Getting image source signatures
# Copying blob sha256:9d16cba9fb961d1aafec9542f2bf7cb64acfc55245f9e4eb5abecd4cdc38d749
# Copying config sha256:961769676411f082461f9ef46626dd7a2d1e2b2a38e6a44364bcbecf51e66dd4
# Writing manifest to image destination
# Storing signatures
# $ /usr/bin/buildah from --security-opt seccomp=/var/tmp/buildah_tests.6b1cxe/seccomp.json --quiet --pull=false --signature-policy /usr/share/buildah/test/system/policy.json alpine
# alpine-working-container
# $ /usr/bin/buildah run --runtime=crun --runtime-flag=debug alpine-working-container true
# /var/str

The broken test is being fixed in #4502; until that merges we can’t actually know what happened. One possibility is that crun changed somehow, such that debug no longer produces debug output? The test failure suggests that this command:

$ buildah run --runtime=crun --runtime-flag=debug alpine-working-container true

…should produce output, but it isn’t? Could this be a crun change? A change in how buildah passes the --runtime-flag option?