On several wikis, such as enwiki, the CheckUserLog has a few entries where the range checked is over the allowed limit of /16 for IPv4. Most are historical, but there are a few recent ones caused by a software bug with how requests for ranges over the limit allowed was handled. When viewing the CheckUserLog these entries do not add any useful info, and for tools that I use on enwiki add a indication that this range has been previously checked.

Ideally these entries should either be hidden when searching by an IP or range, or these entries should be manually removed from the DB as not useful. The second option has been proposed by a checkuser on the checkuser IRC channel.