Google Logging List endpoint does not show application logs though the client library shows them

Question

My Rails application needs to pull filtered logs from Google Cloud. I first implemented it via the official google-cloud-logging library, but the Ruby implementation is painfully slow, and each request takes 15-20 seconds. I tried the API explorer here and it's much faster, however, the result is different - the REST endpoint does not return application logs, so the resource.type=k8s_container filter works with the client library, but not the REST endpoint. Do you know what the problem might be?