Repeat behaviour on new backups - cant restore .env file from filen.io Index was outside the bounds of the array

I got the following error, when trying to restore a .env file to my VPS:
[Error-Duplicati.Library.Main.Operation.Restore.VolumeDownloader-DownloadError]: Error during download\nIndexOutOfRangeException: Index was outside the bounds of the array."

I decided to create a new backup, with different source and destination and a new .env file. The same error occurred when I tried to restore a differrent .env file.

Other files like readme.md could be restored: here is the log from the new backup and restore test:
"2026-02-02 08:21:42 +00 - [Error-Duplicati.Library.Main.Operation.Restore.VolumeDownloader-DownloadError]: Error during download\nIndexOutOfRangeException: Index was outside the bounds of the array.""2026-02-02 08:21:42 +00 - [Error-Duplicati.Library.Main.Operation.Restore.BlockManager-BlockCountError]: Block count in SleepableDictionarys block table is not zero: 2\nFirst 10 blocks: 16058, 16057""2026-02-02 08:21:42 +00 - [Error-Duplicati.Library.Main.Operation.Restore.BlockManager-VolumeCountError]: Volume count in SleepableDictionarys volume table is not zero: 2\nFirst 10 volumes: 7, 9""2026-02-02 08:21:42 +00 - [Error-Duplicati.Library.Main.Controller-FailedOperation]: The operation Restore has failed\nIndexOutOfRangeException: Index was outside the bounds of the array."

Update - if I download the whole duplicati backup folder from filen.io to my local drive, the restore succeeds in restoring the files OK. The error or bug seems to be linked to restoring directly from filen.io.