On 2024.1.5854, the time range selection in the Calendar component is completely broken: the selection is not highlighted and the selected time range is completely off, even outside the displayed range.
Reverting back to 2023.4.5820 immediately solves the problem.
Attached two videos - only change between the recordings is the DayPilot version, once 2024.1.5854 and once 2023.4.5820.