Hy @all,
my problem is solved... It's really true, that the Exchange made his cleanup at the same time, as the Backup was running.
The Problem was, that the Backup was growing up with the speed (it do it faster, every day a little bit faster) and that was the problem with the time difference, because I haven't the problem befor.
In this case, many thanks for your help and I'm sorry, that I haven't found the Problem byself, because it was writing more than 1 time, that the cleanup agent from Exchange made some problem, if the cleanup agent run at the same time, as the backup is runnnig.
Many thanks for your help ;)
I wish you a wunderful day.
Kindly Regards
Diego