C++: Having trouble while reading from file

I was trying to read from a file (this is the file)

at the first object, everything is normal, but something wrong when reload obj 2 (the output below)

I put cout in my code to detect the errors

and this is what I found:

please help to fix the error

01/02/2020:01/02/2023: ho chi minh:1200:10:1:rat la dep 04/04/2021:03/03/2023: da nang:1299:12:1:rat la dep can not load this date into "end" variable, so "end" had to store the next data