could not link file in wal restore lines

I'm doing test restores of the wal with pgbackrest. My problem is that
there are lines like

could not link file "pg_wal/000000010000015600000098" to
"pg_wal/00000001000001570000006E": File exists

appearing in the postgres log on the first startup, when the wal logs are
loaded.

The restore and startup process completes fine, with no corruption AFAIK,
but I'd like to make sure that there is indeed no chance of corruption.

I've opened an issue on pgbackrest, where the developer confirmed that
those files are not touched by pgbackrest, they are basically copied back
exactly as they were. The backup/restore is on the same partition as the
data folder, so no chance of file system changes, etc. Single master, no
replication.

I'm always doing clean data dir + init_db so there is nothing there before
the restore. I can replicate this behaviour 100%.

PostgreSQL version: psql (PostgreSQL) 12.11 (Ubuntu 12.11-1.pgdg18.04+1)

OS is Ubuntu 18.04

pgbackrest issue: https://github.com/pgbackrest/pgbackrest/issues/1815

log details:

could not link file "pg_wal/000000010000015600000098" to
"pg_wal/00000001000001570000006E": File exists

In total, I get 18 lines of "could not link file" and 932 lines of
"restored log file" lines.

At the end it finishes with:

redo done at 15A/A001710
last completed transaction was at log time 2022-07-15 19:41:05.175573+00
restored log file "000000030000015A0000000A" from archive
selected new timeline ID: 4
archive recovery complete
restored log file "00000003.history" from archive
database system is ready to accept connections

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Thanks and regards,
Zsolt