Seafile 8.0.8 & 9.0.5 having sometimes trouble with uploads

Hello,

we have a very strange issue with our Seafile instances.
One instance is a Ubuntu 20.04 server without a firewall and direct nginx proxy and Seafile 8.0.8.
And one instance is a Docker-Instance with a pfSense and a Caddy between with Seafile 9.0.5. (use_go_fileserver = false)

We try to upload a few hundred Gigabytes of files.
In theory there should be no problem because the files are small. Some bigger files working without any issues.

After uploading ~ 5 GB some files getting stuck with an error message.
The interesting thing is I can Cancel the upload, Continue/Skip it or Retry.
When I press Retry I get the same error message again after 10 seconds.

On the server side I have few interesting log messages.
For example:

seafile.log:

2022-05-25 19:45:42 repo-op.c(324): parent_dir /example doesn't exist in repo 98f01b09-6626-4d39-9572-ea55e63191ec.
2022-05-25 19:46:43 repo-op.c(324): parent_dir /example/tests doesn't exist in repo 98f01b09-6626-4d39-9572-ea55e63191ec.
2022-05-25 19:46:44 repo-op.c(324): parent_dir /example/layouts doesn't exist in repo 98f01b09-6626-4d39-9572-ea55e63191ec.
2022-05-25 19:46:44 repo-op.c(324): parent_dir /example/something doesn't exist in repo 98f01b09-6626-4d39-9572-ea55e63191ec.

This seems only like a warning - because the file upload is working when the messages appear.

But in the access log it is very interesting.

/var/log/nginx/seafhttp.access.log

- 87.123.123.123 [25/May/2022:20:01:10 +0000] "POST /seafhttp/upload-api/c3e14689-5d0b-48b5-abec-ddd70a1996d1 HTTP/1.1" 200 40 "-" "Mozilla/5.0" 0.116
- 87.123.123.123 [25/May/2022:20:01:10 +0000] "POST /seafhttp/upload-api/c3e14689-5d0b-48b5-abec-ddd70a1996d1 HTTP/1.1" 200 40 "-" "Mozilla/5.0" 0.076
- 87.123.123.123 [25/May/2022:20:01:12 +0000] "POST /seafhttp/upload-api/c3e14689-5d0b-48b5-abec-ddd70a1996d1 HTTP/1.1" 200 40 "-" "Mozilla/5.0" 0.876
- 87.123.123.123 [25/May/2022:20:01:12 +0000] "POST /seafhttp/upload-api/c3e14689-5d0b-48b5-abec-ddd70a1996d1 HTTP/1.1" 200 40 "-" "Mozilla/5.0" 0.032
- 87.123.123.123 [25/May/2022:20:01:14 +0000] "POST /seafhttp/upload-api/c3e14689-5d0b-48b5-abec-ddd70a1996d1 HTTP/1.1" 200 40 "-" "Mozilla/5.0" 0.476
- 87.123.123.123 [25/May/2022:20:01:15 +0000] "POST /seafhttp/upload-api/c3e14689-5d0b-48b5-abec-ddd70a1996d1 HTTP/1.1" 200 40 "-" "Mozilla/5.0" 0.044

And then … when I get the error message on the client side. I get this log message.

- 87.123.123.123 [25/May/2022:19:58:09 +0000] "POST /seafhttp/upload-api/6f4323fd-20f2-4f3e-8bec-bcc6ef88acbf HTTP/1.1" 400 26 "-" "Mozilla/5.0" 0.004
- 87.123.123.123 [25/May/2022:19:58:18 +0000] "POST /seafhttp/upload-api/6f4323fd-20f2-4f3e-8bec-bcc6ef88acbf HTTP/1.1" 400 26 "-" "Mozilla/5.0" 0.004
- 87.123.123.123 [25/May/2022:19:58:28 +0000] "POST /seafhttp/upload-api/6f4323fd-20f2-4f3e-8bec-bcc6ef88acbf HTTP/1.1" 400 26 "-" "Mozilla/5.0" 0.000
- 87.123.123.123 [25/May/2022:19:58:38 +0000] "POST /seafhttp/upload-api/6f4323fd-20f2-4f3e-8bec-bcc6ef88acbf HTTP/1.1" 400 26 "-" "Mozilla/5.0" 0.000

The difference is the response code.
Working = 200
Not working = 400

When I check the API documentation here: download seafile com/published/web-api/v2.1/file-upload.md

I found only this information:

400 Bad request

For file-uploaded-bytes the 400 could be parent_dir/file_name invalid..
Or for upload-raw-blks-api the 400 means Invalid URL | Access denied | Duplicate progress id | Invalid Seafile-Content-Range.

But for the specific Upload File request:
POST cloud seafile com:8082/upload-api/73c5d117-3bcf-48a0-aa2a-3f48d5274ae3
There is no real information.

Is there a debug mode or something else?

On the Seafile 8.0.8 I was able to upload more files without issues than on the 9.0.5 version.
Maybe when the upload is too fast then there is a problem?

I’ll try soon with enabling the use_go_fileserver = true.

Thanks in Advance for any ideas!