rules_go fails with bazel@HEAD, but not tied to a commit

rules_go fails with bazel@HEAD, but it doesn't seem tied to any particular bazel commit.
The failing tests are coverage-related, and seem to be that the coverage file is not found

https://buildkite.com/bazel/culprit-finder/builds/171#863978e5-2c65-4b87-8f9f-3aa1487bc77c

I also tried triggering the rules_go CI with release Bazel, and got *partial* same failures:

https://buildkite.com/bazel/rules-go-golang/builds/1196

There hasn't been a recent commit in rules_go, so I have to assume this is a CI issue.