Warning "Unable to acquire permit to use snapshot files during recovery…" when restarting elasticsearch node

When upgrading our Elasticsearch cluster to version 7.16.1, we performing a rolling upgarde as described in the documentation. Before the restart we trigger a synced flush and increase cluster.routing.allocation.node_concurrent_recoveries to 32.

After the shard allocation was enabled the node logs multiple multple warings:

Unable to acquire permit to use snapshot files during recovery, this recovery will recover index files from the source node. Ensure snapshot files can be used during recovery by setting [indices.recovery.max_concurrent_snapshot_file_downloads] to be no greater than [25]

We did not changed indices.recovery.max_concurrent_snapshot_file_downloads from the default (5).

What might cause this warning? Is there a known issue when upgrading to 7.16.1?

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After upgrading 7.16.2, we also see above warning. Is it because default(5) is not enough ?

That'd explain it. Don't change this setting.

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