Virustotal works like this: It scans the file using separate Antivirus heuristics and shows each AV's result.
Showing 1 positive doesn't always mean that the file is malicious, it's just with that specific AV.
Among the results, "Undetected" means that the file is safe according to the AVs that reported it.
Given that, it's a single unpopular Antivirus' analysis.
Out of the 70~ish antivirus software listed there (with 10 amongst the popular showing "Undetected"), only "Zillya" reported a positive result.
IMO, that's enough to be considered false-positive.
But if you want to be totally sure that there's no Trojan in your software: "don't trust, verify"
Build Bitcoin Core yourself after auditing the code to check if there's something malicious there.
Link to Bitcoin Core's repo: github.com/bitcoin/bitcoin
The current "reanalyzed" result shows the "1/71" OP originally saw.