The system interpretation of dates that contain years made out of 1 or 2 digits (e.g. MM-YY or MM-Y) is not clearly indicated to users.
For example: a user could attempt to look for events that took place on the 31st of January, and subsequently enter 31-01. The fact that the system interpretation of that value is actually January of the year 31 is not apparent in the UI.
Solution idea: Use an era marker to indicate BCE and CE besides the years in the parsedValue string.
Yeah, we could make the UI explicitly state "CE" for all those dates of the Common Era with one- or two-digit years, in line with https://en.wikipedia.org/wiki/WP:BCE…
One- and two-digit years may look more natural with an era marker (born in 2 AD or born January 15, 22 CE, not born in 2 nor January 15, 22).
This might solve a number of potential confusions.
Is this ticket specifically for the query builder? If so, could you make that a bit clearer, because there's a much older ticket at T104750 for the main Wikidata UI and I nearly marked this one as a duplicate of it before seeing the query builder tag.