I’m using the currently available version 6.2.0. The value stored in Libre Calc isn’t what appears on the display. The value in the cell is “2/25/2019 12:54:00” and value displayed as a time is “12:53”.
Please file a bug report. You may use this minimal reproducing document. (Well - unless @erAck already fixed that :-))
FWIW, bug tdf#123748