ERROR: functions in index predicate must be marked IMMUTABLE when running 14.2 PostgreSQL migrations.

Hello,

When running migrations for 14.2 I experience the following issue :

System Info:
    ------------
    chef_version=15.14.0
    platform=ubuntu
    platform_version=20.04
    ruby=ruby 2.7.2p137 (2020-10-01 revision 5445e04352) [x86_64-linux]
    program_name=/opt/gitlab/embedded/bin/chef-client
    executable=/opt/gitlab/embedded/bin/chef-client
    

Running handlers:
There was an error running gitlab-ctl reconfigure:

rails_migration[gitlab-rails] (gitlab::database_migrations line 51) had an error: Mixlib::ShellOut::ShellCommandFailed: bash[migrate gitlab-rails database] (/opt/gitlab/embedded/cookbooks/cache/cookbooks/gitlab/resources/rails_migration.rb line 16) had an error: Mixlib::ShellOut::ShellCommandFailed: Expected process to exit with [0], but received '1'
---- Begin output of "bash"  "/tmp/chef-script20210823-910351-xkxmw7" ----
STDOUT: rake aborted!
StandardError: An error has occurred, all later migrations canceled:

PG::InvalidObjectDefinition: ERROR:  functions in index predicate must be marked IMMUTABLE
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:154:in `block in add_concurrent_index'
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:358:in `disable_statement_timeout'
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:153:in `add_concurrent_index'
/opt/gitlab/embedded/service/gitlab-rails/db/post_migrate/20210809123658_orphaned_invite_tokens_cleanup.rb:14:in `up'
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/db.rake:61:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/bin/bundle:23:in `load'
/opt/gitlab/embedded/bin/bundle:23:in `<main>'

Caused by:
ActiveRecord::StatementInvalid: PG::InvalidObjectDefinition: ERROR:  functions in index predicate must be marked IMMUTABLE
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:154:in `block in add_concurrent_index'
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:358:in `disable_statement_timeout'
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:153:in `add_concurrent_index'
/opt/gitlab/embedded/service/gitlab-rails/db/post_migrate/20210809123658_orphaned_invite_tokens_cleanup.rb:14:in `up'
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/db.rake:61:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/bin/bundle:23:in `load'
/opt/gitlab/embedded/bin/bundle:23:in `<main>'

Caused by:
PG::InvalidObjectDefinition: ERROR:  functions in index predicate must be marked IMMUTABLE
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:154:in `block in add_concurrent_index'
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:358:in `disable_statement_timeout'
/opt/gitlab/embedded/service/gitlab-rails/lib/gitlab/database/migration_helpers.rb:153:in `add_concurrent_index'
/opt/gitlab/embedded/service/gitlab-rails/db/post_migrate/20210809123658_orphaned_invite_tokens_cleanup.rb:14:in `up'
/opt/gitlab/embedded/service/gitlab-rails/lib/tasks/gitlab/db.rake:61:in `block (3 levels) in <top (required)>'
/opt/gitlab/embedded/bin/bundle:23:in `load'
/opt/gitlab/embedded/bin/bundle:23:in `<main>'
Tasks: TOP => db:migrate
(See full trace by running task with --trace)
== 20210809123658 OrphanedInviteTokensCleanup: migrating ======================
-- transaction_open?()
   -> 0.0000s
-- index_exists?("members", :id, {:where=>"invite_token IS NOT NULL and invite_accepted_at IS NOT NULL and invite_accepted_at < created_at", :name=>"tmp_idx_orphaned_invite_tokens", :algorithm=>:concurrently})
   -> 0.0075s
-- execute("SET statement_timeout TO 0")
   -> 0.0002s
-- add_index("members", :id, {:where=>"invite_token IS NOT NULL and invite_accepted_at IS NOT NULL and invite_accepted_at < created_at", :name=>"tmp_idx_orphaned_invite_tokens", :algorithm=>:concurrently})
-- execute("RESET statement_timeout")
   -> 0.0003s
STDERR: 
---- End output of "bash"  "/tmp/chef-script20210823-910351-xkxmw7" ----
Ran "bash"  "/tmp/chef-script20210823-910351-xkxmw7" returned 1