Censys expands queries to provide additional functionality. For example, the query a:zmap.io
executes a DNS lookup and expands to ip:184.108.40.206.
Your query was changed from:
parsed.tbs_noct_fingerprint: a4139421d771d7a9b5d07161cc6e3b4fc4e44bd124d364e9eb5c5649b77a9f52 and precert: true
parsed.tbs_noct_fingerprint: a4139421d771d7a9b5d07161cc6e3b4fc4e44bd124d364e9eb5c5649b77a9f52 AND precert: true
If this isn't what you intended, you can run your raw query without expansion.