Advanced Search in self-hosted Gitlab doesn't search in issues

Hello,

We have self-managed Gitlab v.16.3.5 and Elasticsearch v.8.10.2 on same server.

When we search for a phrase definitely present in Issues -- Advanced Search finds nothing, even when we search in exact project. Meanwhile it can find in commits, code, or wiki.

Advanced Search is enabled, indexes were rebuilt several times from scratch, no migrations pending, no limited projects, elasticsearch.log or sidekiq.log show no apparent errors. It looks like Elasticsearch simply doesn't index Issues (and probably something else).

Regards,