Unable to confirm deletion of a specific user

Summary

When trying to delete a user, confirmation modal won't enable the delete button even though the user's name is correctly typed in/copy-pasted

Steps to reproduce

It happens on my instance so I don't know how I can tell how to reproduce it.

What is the current bug behavior?

The "delete user and all contributions" button is greyed out when typing the user name for confirmation

What is the expected correct behavior?

The button should be enabled.

Relevant logs and/or screenshots

Here's a screenshot.

Note that this bug doesn't happen on any other user I've tried to delete. I occasionally receive some spam account registrations but swiftly deal with them. This one, however, is not deletable and I have no idea why.

I also tripled checked I didn't put a space before or after my copy/paste.

Output of checks

Results of GitLab environment info

Expand for output related to GitLab environment info

System information
System:         Ubuntu 16.04
Current User:   git
Using RVM:      no
Ruby Version:   2.6.6p146
Gem Version:    2.7.10
Bundler Version:1.17.3
Rake Version:   12.3.3
Redis Version:  5.0.9
Git Version:    2.28.0
Sidekiq Version:5.2.9
Go Version:     unknown

GitLab information
Version:        13.5.3
Revision:       eaa194f15e6
Directory:      /opt/gitlab/embedded/service/gitlab-rails
DB Adapter:     PostgreSQL
DB Version:     11.9
URL:            https://lab.shelter.moe
HTTP Clone URL: https://lab.shelter.moe/some-group/some-project.git
SSH Clone URL:  git@shelter.mahoro-net.org:some-group/some-project.git
Using LDAP:     no
Using Omniauth: yes
Omniauth Providers: gitlab, google_oauth2, twitter, github

GitLab Shell
Version:        13.11.0
Repository storage paths:
- default:      /var/opt/gitlab/git-data/repositories
GitLab Shell path:              /opt/gitlab/embedded/service/gitlab-shell
Git:            /opt/gitlab/embedded/bin/git

Results of GitLab application Check

Expand for output related to the GitLab application check

Checking GitLab subtasks ...
Checking GitLab Shell ...
GitLab Shell: ... GitLab Shell version >= 13.11.0 ? ... OK (13.11.0)
Running /opt/gitlab/embedded/service/gitlab-shell/bin/check
Internal API available: OK
Redis available via internal API: OK
gitlab-shell self-check successful
Checking GitLab Shell ... Finished
Checking Gitaly ...
Gitaly: ... default ... OK
Checking Gitaly ... Finished
Checking Sidekiq ...
Sidekiq: ... Running? ... yes
Number of Sidekiq processes ... 1
Checking Sidekiq ... Finished
Checking Incoming Email ...
Incoming Email: ... Checking Reply by email ...
IMAP server credentials are correct? ... Checking shelter.lab@mahoro-net.org
yes
Init.d configured correctly? ... skipped
MailRoom running? ... skipped
Checking Reply by email ... Finished
Checking Incoming Email ... Finished
Checking LDAP ...
LDAP: ... LDAP is disabled in config/gitlab.yml
Checking LDAP ... Finished
Checking GitLab App ...
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: ...
264/2 ... yes
2/4 ... yes
1/6 ... yes
1/7 ... yes
1/8 ... yes
7/9 ... yes
19/10 ... yes
4/11 ... yes
22/12 ... yes
156/13 ... yes
15/14 ... yes
8/15 ... yes
5/18 ... yes
45/22 ... yes
156/23 ... yes
52/24 ... yes
52/25 ... yes
59/26 ... yes
155/28 ... yes
62/32 ... yes
62/33 ... yes
52/34 ... yes
155/35 ... yes
5/36 ... yes
54/40 ... yes
67/41 ... yes
67/43 ... yes
67/44 ... yes
156/45 ... yes
65/46 ... yes
66/47 ... yes
82/52 ... yes
96/55 ... yes
82/59 ... yes
8/65 ... yes
7/66 ... yes
5/67 ... yes
253/68 ... yes
82/69 ... yes
20/70 ... yes
45/71 ... yes
110/72 ... yes
82/73 ... yes
8/74 ... yes
8/75 ... yes
8/76 ... yes
156/77 ... yes
9/80 ... yes
66/81 ... yes
78/83 ... yes
1/87 ... yes
135/89 ... yes
126/90 ... yes
135/91 ... yes
135/92 ... yes
135/93 ... yes
1/98 ... yes
153/99 ... yes
155/100 ... yes
155/101 ... yes
5/102 ... yes
8/106 ... yes
45/107 ... yes
102/109 ... yes
129/110 ... yes
5/111 ... yes
9/112 ... yes
198/113 ... yes
102/114 ... yes
198/115 ... yes
193/116 ... yes
45/118 ... yes
135/119 ... yes
107/120 ... yes
5/129 ... yes
135/130 ... yes
5/131 ... yes
52/132 ... yes
1/133 ... yes
1/134 ... yes
228/135 ... yes
193/136 ... yes
228/137 ... yes
1/139 ... yes
236/141 ... yes
253/142 ... yes
3/144 ... yes
102/145 ... yes
36/146 ... yes
193/147 ... yes
193/148 ... yes
250/149 ... yes
253/151 ... yes
253/152 ... yes
254/153 ... yes
193/155 ... yes
193/156 ... yes
193/157 ... yes
193/158 ... yes
253/159 ... yes
1/161 ... yes
228/162 ... yes
228/163 ... yes
264/164 ... yes
5/165 ... yes
5/167 ... yes
52/169 ... yes
9/172 ... yes
305/173 ... yes
305/174 ... yes
305/175 ... yes
155/176 ... yes
305/178 ... yes
16/181 ... yes
305/182 ... yes
52/183 ... yes
4/192 ... yes
52/193 ... yes
382/195 ... yes
388/196 ... yes
193/197 ... yes
5/198 ... yes
372/200 ... yes
388/201 ... yes
387/202 ... yes
388/203 ... yes
Redis version >= 4.0.0? ... yes
Ruby version >= 2.5.3 ? ... yes (2.6.6)
Git version >= 2.24.0 ? ... yes (2.28.0)
Git user has default SSH configuration? ... yes
Active users: ... 230
Is authorized keys file accessible? ... yes
GitLab configured to store new projects in hashed storage? ... yes
All projects are in hashed storage? ... no
Try fixing it:
Please migrate all projects to hashed storage
as legacy storage is deprecated in 13.0 and support will be removed in 14.0.
For more information see:
doc/administration/repository_storage_types.md
Checking GitLab App ... Finished
Checking GitLab subtasks ... Finished