Censys expands queries to provide additional functionality. For example, the query a:zmap.io
executes a DNS lookup and expands to ip:220.127.116.11.
Your query was changed from:
parsed.names: (dns_names or 2f5d2e90ceeb14fc9c600cbbfbaf0428.io)
parsed.names: (dns_names OR 2f5d2e90ceeb14fc9c600cbbfbaf0428.io)
If this isn't what you intended, you can run your raw query without expansion.