2020/05/13 19:50:57 DEBUG : rclone: Version "v1.51.0" starting with parameters ["rclone" "copy" "putio:test_folder/" "/home/agneev/fwb" "--multi-thread-streams" "6" "-vv" "--buffer-size" "128M" "--dry-run"]
2020/05/13 19:50:57 DEBUG : Using config file from "/home/agneev/.config/rclone/rclone.conf"
2020/05/13 19:50:59 ERROR : : error reading source directory: directory not found
2020/05/13 19:50:59 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 19:50:59 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 19:50:59 ERROR : Attempt 1/3 failed with 1 errors and: directory not found
2020/05/13 19:50:59 ERROR : : error reading source directory: directory not found
2020/05/13 19:50:59 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 19:50:59 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 19:50:59 ERROR : Attempt 2/3 failed with 1 errors and: directory not found
2020/05/13 19:50:59 ERROR : : error reading source directory: directory not found
2020/05/13 19:50:59 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 19:50:59 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 19:50:59 ERROR : Attempt 3/3 failed with 1 errors and: directory not found
2020/05/13 19:50:59 Failed to copy: directory not found
Copying from the mount:
agneev@pi4:~ $ rclone copy /mnt/putio/test_folder/ ~/fwb --multi-thread-streams 6 -vv --buffer-size 128M --dry-run
2020/05/13 19:51:31 DEBUG : rclone: Version "v1.51.0" starting with parameters ["rclone" "copy" "/mnt/putio/test_folder/" "/home/agneev/fwb" "--multi-thread-streams" "6" "-vv" "--buffer-size" "128M" "--dry-run"]
2020/05/13 19:51:31 DEBUG : Using config file from "/home/agneev/.config/rclone/rclone.conf"
2020/05/13 19:51:33 NOTICE: test.mkv: Not copying as --dry-run
2020/05/13 19:51:33 NOTICE: test2.txt: Not copying as --dry-run
2020/05/13 19:51:33 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 19:51:33 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 19:51:33 NOTICE: test3.nfo: Not copying as --dry-run
2020/05/13 19:51:33 INFO :
Transferred: 0 / 0 Bytes, -, 0 Bytes/s, ETA -
Transferred: 3 / 3, 100%
Elapsed time: 0.0s
2020/05/13 19:51:33 DEBUG : 3 go routines active
2020/05/13 19:51:33 DEBUG : rclone: Version "v1.51.0" finishing with parameters ["rclone" "copy" "/mnt/putio/test_folder/" "/home/agneev/fwb" "--multi-thread-streams" "6" "-vv" "--buffer-size" "128M" "--dry-run"]
Apparently the trailing slash (rclone copy putio:test_folder /) is causing the issue...
Without it, it works as expected...
agneev@pi4:~ $ rclone copy putio:Snitch.2013.1080p.BluRay.x264.TrueHD.7.1.Atmos-SWTYBLZ/ ~/fwb --multi-thread-streams 6 -vv --buffer-size 128M --dry-run
2020/05/13 22:30:08 DEBUG : rclone: Version "v1.51.0" starting with parameters ["rclone" "copy" "putio:Snitch.2013.1080p.BluRay.x264.TrueHD.7.1.Atmos-SWTYBLZ/" "/home/agneev/fwb" "--multi-thread-streams" "6" "-vv" "--buffer-size" "128M" "--dry-run"]
2020/05/13 22:30:08 DEBUG : Using config file from "/home/agneev/.config/rclone/rclone.conf"
2020/05/13 22:30:10 ERROR : : error reading source directory: directory not found
2020/05/13 22:30:10 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 22:30:10 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 22:30:10 ERROR : Attempt 1/3 failed with 1 errors and: directory not found
2020/05/13 22:30:10 ERROR : : error reading source directory: directory not found
2020/05/13 22:30:10 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 22:30:10 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 22:30:10 ERROR : Attempt 2/3 failed with 1 errors and: directory not found
2020/05/13 22:30:11 ERROR : : error reading source directory: directory not found
2020/05/13 22:30:11 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 22:30:11 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 22:30:11 ERROR : Attempt 3/3 failed with 1 errors and: directory not found
2020/05/13 22:30:11 Failed to copy: directory not found
agneev@pi4:~ $ rclone copy putio:Snitch.2013.1080p.BluRay.x264.TrueHD.7.1.Atmos-SWTYBLZ ~/fwb --multi-thread-streams 6 -vv --buffer-size 128M --dry-run
2020/05/13 22:30:18 DEBUG : rclone: Version "v1.51.0" starting with parameters ["rclone" "copy" "putio:Snitch.2013.1080p.BluRay.x264.TrueHD.7.1.Atmos-SWTYBLZ" "/home/agneev/fwb" "--multi-thread-streams" "6" "-vv" "--buffer-size" "128M" "--dry-run"]
2020/05/13 22:30:18 DEBUG : Using config file from "/home/agneev/.config/rclone/rclone.conf"
2020/05/13 22:30:20 NOTICE: RARBG.txt: Not copying as --dry-run
2020/05/13 22:30:20 NOTICE: Snitch.2013.1080p.BluRay.x264.TrueHD.7.1.Atmos-SWTYBLZ.mkv: Not copying as --dry-run
2020/05/13 22:30:20 INFO : Local file system at /home/agneev/fwb: Waiting for checks to finish
2020/05/13 22:30:20 INFO : Local file system at /home/agneev/fwb: Waiting for transfers to finish
2020/05/13 22:30:20 INFO :
Transferred: 0 / 0 Bytes, -, 0 Bytes/s, ETA -
Transferred: 2 / 2, 100%
Elapsed time: 0.0s
2020/05/13 22:30:20 DEBUG : 4 go routines active
2020/05/13 22:30:20 DEBUG : rclone: Version "v1.51.0" finishing with parameters ["rclone" "copy" "putio:Snitch.2013.1080p.BluRay.x264.TrueHD.7.1.Atmos-SWTYBLZ" "/home/agneev/fwb" "--multi-thread-streams" "6" "-vv" "--buffer-size" "128M" "--dry-run"]
I'd assume with putio, it's trying to find a directory matching that to transfer but not a file based on your two tests. In general, a trailing slash is looking for a directory rather than a file so if you are looking for a file, it's best to not use a trailing /.