Internal server error when removing projects

I've updated my self hosted gitlab instance to 11.9, and can't remove any projects since then. Removing groups containing projects does work though.

The log shows the following stack trace:

Completed 500 Internal Server Error in 17ms (ActiveRecord: 2.9ms)

OpenSSL::Cipher::CipherError ():

lib/gitlab/crypto_helper.rb:27:in `aes256_gcm_decrypt'
app/models/concerns/token_authenticatable_strategies/encrypted.rb:45:in `get_token'
app/models/concerns/token_authenticatable_strategies/base.rb:27:in `ensure_token'
app/models/concerns/token_authenticatable_strategies/encrypted.rb:32:in `ensure_token'
app/models/concerns/token_authenticatable.rb:38:in `block in add_authentication_token_field'
app/services/projects/destroy_service.rb:13:in `async_execute'
app/controllers/projects_controller.rb:146:in `destroy'
lib/gitlab/i18n.rb:55:in `with_locale'
lib/gitlab/i18n.rb:61:in `with_user_locale'
app/controllers/application_controller.rb:434:in `set_locale'
lib/gitlab/middleware/multipart.rb:103:in `call'
lib/gitlab/request_profiler/middleware.rb:16:in `call'
lib/gitlab/middleware/go.rb:20:in `call'
lib/gitlab/etag_caching/middleware.rb:13:in `call'
lib/gitlab/middleware/correlation_id.rb:16:in `block in call'
lib/gitlab/correlation_id.rb:15:in `use_id'
lib/gitlab/middleware/correlation_id.rb:15:in `call'
lib/gitlab/middleware/read_only/controller.rb:40:in `call'
lib/gitlab/middleware/read_only.rb:18:in `call'
lib/gitlab/middleware/basic_health_check.rb:25:in `call'
lib/gitlab/request_context.rb:26:in `call'
lib/gitlab/metrics/requests_rack_middleware.rb:29:in `call'
lib/gitlab/middleware/release_env.rb:13:in `call'

I've already had a similar issue with the runners page not being accessible, showing similar log entries, which was fixed by resetting the runner token.