The FIMS expiry date is calculated year on year from issuance which
is +1year, -1day.
The FIMS issue date is also calculated as -1year, +1day from the day of the latest expiry.
Huang En’s first issue was on 26th February 2014.
Her expiry from the calculation and on every anniversary should be the 25th of February year on year from renewal.
A bug affected the calculation of the expiry date which was calculated manually pre-migration and was calculated manually and fed to the database.
This was fixed permanently (hardcoded) after the migration of the FIMS records in October 2018 (which was to achieve one database of all records of both citizens and non-citizens).
Regardless of the time of renewal, your expiry and issuance dates stay the same using the formula in points 1 and 2 respectively.
Huang En’s record gained a day as a result of the bug hence the issuance date changing from the 26th of February to the 27th of February year on year.
This has also inevitably led to a gain of +1 day on the day of expiry year on year from the 25th of February to the 26th of February year on year.