Waiting for metadata download stream to finish

I recently noted additional line in UrBackup reports: “Waiting for metadata download stream to finish”. Should I worry about this?

It does not appear in every report, but in most of them and it is not client specific. All backups are reported as successes regardless of presence of “Waiting for metadata download stream to finish” in report.

This started happening after server kernel update and mbo+cpu+ram upgrade. Server OS is Linux Mint 19.3 kernel 5.4.0.42 (backup on mirrored btrfs HDDs) and UrBackup server version is 2.4.13, all clients run Win 10.

Now all backup reports have “Waiting for metadata download stream to finish”. All backup are still reported as successes with no errors or warnings. I have not noticed any slowdown during backup procedure, backuping takes roughly the same time as before.
Does anyone know why “Waiting for metadata download stream to finish” started to appear in reports.

Waiting for metadata download stream to finish - typically adds 2 minutes to backup time.

Report:
( 18 infos, 0 warnings, 0 errors)

2020-07-03 07:51:23(info): Starting scheduled incremental file backup…
2020-07-03 07:51:37(info): Selected no components to backup
2020-07-03 07:51:37(info): Scanning for changed hard links on volume of “D:”…
2020-07-03 07:51:37(info): Indexing of “*****” done. 10 filesystem lookups 4299 db lookups and 5 db updates
2020-07-03 07:51:37(info): *: Loading file list…
2020-07-03 07:51:37(info): *: Calculating file tree differences…
2020-07-03 07:51:37(info): *: Creating snapshot…
2020-07-03 07:51:38(info): *: Deleting files in snapshot… (10)
2020-07-03 07:51:38(info): *: Deleting files in hash snapshot…(10)
2020-07-03 07:51:38(info): *: Calculating tree difference size…
2020-07-03 07:51:38(info): *: Linking unchanged and loading new files…
2020-07-03 07:51:39(info): Waiting for file transfers…
2020-07-03 07:51:43(info): Waiting for file hashing and copying threads…
2020-07-03 07:51:44(info): Writing new file list…
2020-07-03 07:51:44(info): All metadata was present
2020-07-03 07:51:46(info): Transferred 87.4938 MB - Average speed: 123.727 MBit/s
2020-07-03 07:51:53(info): Time taken for backing up client M: 30s
2020-07-03 07:51:53(info): Backup succeeded

Report:
( 19 infos, 0 warnings, 0 errors)

2020-09-16 08:22:09(info): Starting scheduled incremental file backup…
2020-09-16 08:22:23(info): Selected no components to backup
2020-09-16 08:22:23(info): Scanning for changed hard links on volume of “D:”…
2020-09-16 08:22:23(info): Indexing of “*****” done. 8 filesystem lookups 4338 db lookups and 6 db updates
2020-09-16 08:22:23(info): *: Loading file list…
2020-09-16 08:22:23(info): *: Calculating file tree differences…
2020-09-16 08:22:23(info): *: Creating snapshot…
2020-09-16 08:22:23(info): *: Deleting files in snapshot… (21)
2020-09-16 08:22:23(info): *: Deleting files in hash snapshot…(21)
2020-09-16 08:22:24(info): *: Calculating tree difference size…
2020-09-16 08:22:24(info): *: Linking unchanged and loading new files…
2020-09-16 08:22:24(info): Waiting for file transfers…
2020-09-16 08:22:28(info): Waiting for file hashing and copying threads…
2020-09-16 08:22:30(info): Waiting for metadata download stream to finish
2020-09-16 08:24:28(info): Writing new file list…
2020-09-16 08:24:28(info): All metadata was present
2020-09-16 08:24:29(info): Transferred 69.8186 MB - Average speed: 106.857 MBit/s
2020-09-16 08:24:29(info): Time taken for backing up client M: 2m 20s
2020-09-16 08:24:29(info): Backup succeeded

Kernel update resolved the issue.