diffIn methods return inaccurate results if the difference between datetimes is less than a day

[toby-dixon]

a = Carbon() # Create new instance -> now()
b = Carbon() # Create new instance -> now()

b = b.addSeconds(12) # Add seconds to b
print(b.diffInSeconds(a), a.toDateTimeString(), b.toDateTimeString())
# Prints 0 2024-12-13 15:45:41 2024-12-13 15:45:53

b = b.addMinutes(12) # Add seconds to b
print(b.diffInSeconds(a), a.toDateTimeString(), b.toDateTimeString())
# Prints 0 2024-12-13 15:45:41 2024-12-13 15:57:53

b = b.addHours(12) # Add seconds to b
print(b.diffInSeconds(a), a.toDateTimeString(), b.toDateTimeString())
# Prints 0 2024-12-13 15:45:41 2024-12-14 03:57:53

b = b.addDays(12) # Add seconds to b
print(b.diffInSeconds(a), a.toDateTimeString(), b.toDateTimeString())
# Prints 1036800 2024-12-13 15:46:48 2024-12-26 03:59:00