why using 'skip_resolve_phase_with_proxy: true'

Hello，
Why do I need to enable skip_resolve_phase_with_proxy: true in my module when using proxy? Is DNS resolution not required when using a proxy?

Factually，
when using proxy，
Open 'skip_resolve_phase_with_proxy: true' will cause 'probe_dns_lookup_time_seconds{instance=~"https://example.com"}' is none.
Off 'skip_resolve_phase_with_proxy: true' will cause the entire detection to fail.