hi, I ran a backup test from standby. I found restore from fullback the data was complete, but when add delta backup, after restore, some data between full and delta backup is lost. I did the test several times,whether archive or stream ,stream mode is more obvious,almost 4 of 5 some data was lost.

pg_probackup version 2.5.2 (install from rpm)
pg version 11.14
steps to reproduce

1. add instance
   pg_probackup-11 add-instance -B /var/lib/pgsql/backdir/ -D /var/lib/pgsql/test/ --instance standbytest --remote-proto=ssh --remote-host=192.168.56.15 --remote-port=22 --remote-user=postgres --remote-path=/usr/bin
2. add master info for switch wal
   pg_probackup-11 set-config --instance standbytest -U backup -h 192.168.56.20 -p 5432
3. take a full backup
   pg_probackup-11 backup --instance standbytest --remote-user=postgres --remote-host=192.168.56.15 --remote-port=22 -b full
4. insert some rows and create a new table
   5.take a delta backup
   pg_probackup-11 backup --instance standbytest --remote-user=postgres --remote-host=192.168.56.15 --remote-port=22 -b delta
   6 restore
   pg_probackup-11 restore --instance standbytest --recovery-target-time='2022-02-18 16:04:16' -D /var/lib/pgsql/test