Back In Time (BIT) Restore Fails on 20.04 with rsync error

I just installed the current Xubuntu 20.04 and tried to restore my backup from my backintime backup via sshfs. Unfortunately, this failed. I checked the full log in /home/user/.local/share/backintime/restore_3.log

It has about 450k lines, where the most important ones are:

receiving file list ... done
rsync: failed to set times on "/home": Operation not permitted (1)
home/
home/user/
home/user/.ICEauthority
[... 450k lines of restored files ...]
sent 7.47M bytes  received 464.32G bytes  47.33M bytes/sec
total size is 464.22G  speedup is 1.00
rsync error: some files/attrs were not transferred (see previous errors) (code 23) at main.c(1677) [generator=3.1.3]

Restore permissions:
chmod /home/user/.config/xfce4/xfconf/xfce-perchannel-xml/xfce4-notifyd.xml 100644
chmod /home/user/.config/xfce4/xfconf/xfce-perchannel-xml/thunar.xml 100644

Restore permissions: Done

Some questions I have:

1. Is the only error that backintime couldn't set attributes on /home?
2. If yes to 1): Why would backintime set attributes on /home? I backupped /home/user/
3. If no: How do I find missing files and attributes? I searched for 'error' and 'fail' in the aforementioned log, without success.
4. received 464.32G vs. total size is 464.22G. Why?
5. Backintime didn't finish. It was just at 99% for some time when I lost patience and closed it. How do I know, if it was finished?

Thanks!