You don't understand the startdates?
Take, for example, 20251227.0639
Let me stick some spaces in some helpful places:
2025 12 27 . 06 39
That better?
20251227 means 27th December 2025, and 0639 is in 24-hour clock format, IE 6:39AM
Stardates in the Star Trek universe work in an entirely different way. Wikipedia has a good explanation on how Stardates work.