GPG signature verification fails or only partly verifies (first few commits)

Summary

GPG verification is sketchy at best, broken at worst.

Some of my projects (smaller number of commits) verify my sig for some commits, but not all. Other projects with larger number of commits seem to fail entirely with an HTTP 500 error and an 'oops, something went wrong our end' error message.

Here's 2 consecutive commits in a smaller project. Both are signed with the same key, but not both are verified. In fact, for this project, only the first 8 sigs are verified, every one after that is unverified, despite using the same key.

I'm proxying to GitLab from an Apache 2.4 front end. I've been doing this since I started running GitLab and it's been fine. I tried changing the API version in the proxy config in Apache to v4 too but again to no avail.

What is the current bug behavior?

Mix of verified and unverified GPG signatures or HTTP 500 errors and no verification, just a "waiting spinner" where the verified status would be in case of 500 error.

What is the expected correct behavior?

All commits should show verified. I've signed every commit for every project with the same key within my GitLab instance.

Relevant logs and/or screenshots

HTTP 500 error causes this:

Mixed verification shows as:

Output of checks

(If you are reporting a bug on GitLab.com, write: This bug happens on GitLab.com)

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:		Debian 9.1
Current User:	git
Using RVM:	no
Ruby Version:	2.3.3p222
Gem Version:	2.6.6
Bundler Version:1.13.7
Rake Version:	12.0.0
Redis Version:	3.2.5
Git Version:	2.13.5
Sidekiq Version:5.0.4
Go Version:	unknown
GitLab information
Version:	9.5.0
Revision:	77bfdac
Directory:	/opt/gitlab/embedded/service/gitlab-rails
DB Adapter:	postgresql
URL:		https://domain.tld
HTTP Clone URL:	https://domain.tld/some-group/some-project.git
SSH Clone URL:	ssh://git@domain.tld/some-group/some-project.git
Using LDAP:	no
Using Omniauth:	no
GitLab Shell
Version:	5.8.0
Repository storage paths:

• default: /var/opt/gitlab/git-data/repositories Hooks: /opt/gitlab/embedded/service/gitlab-shell/hooks Git: /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab Shell ...
GitLab Shell version >= 5.8.0 ? ... OK (5.8.0)
Repo base directory exists?
default... yes
Repo storage directories are symlinks?
default... no
Repo paths owned by git:root, or git:git?
default... yes
Repo paths access is drwxrws---?
default... yes
hooks directories in repos are links: ...
13/1 ... ok
2/2 ... ok
2/3 ... ok
2/4 ... ok
2/5 ... ok
2/6 ... repository is empty
2/7 ... ok
10/9 ... ok
2/10 ... ok
5/12 ... ok
5/13 ... ok
2/14 ... ok
5/15 ... ok
9/16 ... repository is empty
8/17 ... ok
8/18 ... repository is empty
10/19 ... repository is empty
13/25 ... ok
13/31 ... ok
13/32 ... ok
13/33 ... ok
13/34 ... ok
13/36 ... ok
14/40 ... ok
13/42 ... ok
2/43 ... ok
2/44 ... ok
2/45 ... ok
2/46 ... repository is empty
14/47 ... ok
2/48 ... ok
2/50 ... ok
2/51 ... ok
2/52 ... ok
2/53 ... ok
15/55 ... ok
15/56 ... ok
15/57 ... ok
15/58 ... ok
2/59 ... ok
16/60 ... ok
5/61 ... ok
2/62 ... repository is empty
2/63 ... ok
18/66 ... ok
2/67 ... ok
2/68 ... ok
18/69 ... ok
18/70 ... ok
15/71 ... ok
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Check GitLab API access: OK
Access to /var/opt/gitlab/.ssh/authorized_keys: OK
Send ping to redis server: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Sidekiq ...
Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Reply by email ...
Reply by email is disabled in config/gitlab.yml
Checking Reply by email ... Finished
Checking LDAP ...
LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab ...
Git configured correctly? ... yes
Database config exists? ... yes
All migrations up? ... yes
Database contains orphaned GroupMembers? ... no
GitLab config exists? ... yes
GitLab config up to date? ... yes
Log directory writable? ... yes
Tmp directory writable? ... yes
Uploads directory exists? ... yes
Uploads directory has correct permissions? ... yes
Uploads directory tmp has correct permissions? ... yes
Init script exists? ... skipped (omnibus-gitlab has no init script)
Init script up-to-date? ... skipped (omnibus-gitlab has no init script)
Projects have namespace: ...
13/1 ... yes
2/2 ... yes
2/3 ... yes
2/4 ... yes
2/5 ... yes
2/6 ... yes
2/7 ... yes
10/9 ... yes
2/10 ... yes
5/12 ... yes
5/13 ... yes
2/14 ... yes
5/15 ... yes
9/16 ... yes
8/17 ... yes
8/18 ... yes
10/19 ... yes
13/25 ... yes
13/31 ... yes
13/32 ... yes
13/33 ... yes
13/34 ... yes
13/36 ... yes
14/40 ... yes
13/42 ... yes
2/43 ... yes
2/44 ... yes
2/45 ... yes
2/46 ... yes
14/47 ... yes
2/48 ... yes
2/50 ... yes
2/51 ... yes
2/52 ... yes
2/53 ... yes
15/55 ... yes
15/56 ... yes
15/57 ... yes
15/58 ... yes
2/59 ... yes
16/60 ... yes
5/61 ... yes
2/62 ... yes
2/63 ... yes
18/66 ... yes
2/67 ... yes
2/68 ... yes
18/69 ... yes
18/70 ... yes
15/71 ... yes
Redis version >= 2.8.0? ... yes
Ruby version >= 2.3.3 ? ... yes (2.3.3)
Git version >= 2.7.3 ? ... yes (2.13.5)
Active users: ... 2
Checking GitLab ... Finished