Domain has WHOIS info, but rdapper returns none

[adrukh]

For the gitpod.io domain, rdapper is unable to fetch registration info, whereas a WHOIS lookup returns some valid and some confusing data.

From a quick look at the flow for this specific case:

1. RDAP lookup fails, proceed to WHOIS lookup
2. WHOIS lookup against whois.nic.io provides data, but also includes a referral to whois.udag.net
3. WHOIS lookup against whois.udag.net says 'not found'
4. Lookup returns no data, eventually

Suggested solution - coalesce WHOIS referral responses one on top of the other, letting actual data overwrite previously obtained data?

[adrukh]

Additional domains exhibiting this pattern:
pdfflow.io, hairtect.jp, iba.com.br