Error in Log when Importing Documents

In Sage CRM v2023 R2, when we Import a document, from the CRM nterface, everything looks Ok and document can be consulted.

But in the Logs (File: current_sdata.log), we see this error:

ERROR [http-nio-10001-exec-7]: 18-Apr-2024 23:23:46.229 Error uploading document - error message: PARAM_USERFOLDER null

One of our customer is asking the question.
I was able to replicate the issue in a standard install without customizations, but I can't find this parameter anywhere in the database and can't find any documentation related to this issue.

Any comment would be appreciated.

Thanks