Quoting from an older post - even if it was about a different topic:
The problem is that sequential DHCP servers are still out there. And, actually, a large number of them. Many simple ISP-provided routers but also the cheaper, e.g., TP-Link or Netgear ones do this IIRC. Hostnames are updated once per hour by FTL for all known devices. This will account for the situation described in the quote (same IP used by two devices on two days). However, there is no such possibility for the database. We'd have to store the hostname in the database at the time the query is made to be sure we know the right name for this IP at that time.
We discussed this somewhere in the past and did some benchmarks. The result was about 30-50% in database size increase when storing the hostname for each query. So a typical database with a size of 3 GB can almost double in size. This seems unacceptable for what we are trying to achieve here. I'd rather rewrite the database altogether using linked-lists with domain and client tables linked by foreign keys. However, this is something not easily done and also nothing we could upgrade existing databases to (processing a full year worth of queries could take days on a Raspberry Pi).
TL;DR We should remove even try to resolve hostnames from the long-term pages altogether. It is inherently broken at this time.