The error message was introduced win Resilio Active Everywhere platform v4.0.0.
The error message appears only on a Windows OS, and in a very specific case, mostly characteristics for FSLogix use case. Seeing this error message means that the mention file got locked (opened in an application) on an Agent, while it was downloading the file updated from remote Agents.
To fix that, stop the process that keeps the file open.
Error code SE_FS_FILE_UPDATE_COLLISION