using https_proxy in gitaly environment breaks communication with rails since 11.6

We configure the gitaly as such:

gitaly['env'] = {
  "http_proxy" => "http://xxx",
  "https_proxy" => "http://xxx",
 }

This allowed gitaly to access and mirror git repo stored outside of our VPC/intranet.

Since we upgraded from 11.4 to 11.6, then the gitaly cannot communicate anymore with rails, and we get traces like this in production.log:

Gitlab::Git::CommandError (4:Deadline Exceeded):
  lib/gitlab/git/wraps_gitaly_errors.rb:13:in `rescue in wrapped_gitaly_errors'
  lib/gitlab/git/wraps_gitaly_errors.rb:6:in `wrapped_gitaly_errors'
  lib/gitlab/git/blob.rb:79:in `batch_lfs_pointers'
  lib/extracts_path.rb:146:in `lfs_blob_ids'

Removing https?_proxy from env fixed the problem, but no more gitaly mirroring for us. configuring the no_proxy variable for localhost and 127.0.0.1 do not fix the problem.