Gaps in prometheus scraping

Hello
Prometheus version 2.34.0

We use serverset SD to discover our spark targets

The spark service has two endpoints
/metrics/prometheus
/metrics/executor/prometheus

They run on the same port

What’s weird is, we are noticing some gaps in /metrics/prometheus but no gaps in metrics from /metrics/executor/prometheus. The latter is much slower compared to the former scrape. We know for a fact we don’t reach the scrape timeouts

They are spawned as two separate jobs in prometheus. Can duplicate targets be a problem?

I see a lot of logs in Zk treecache package. How can we enable debug logs?
Thanks!