When in LiteSpeed for SQL Server and in the transaction log reader module you will notice the User info tab has missing information. Only the SPID will be available.
This is a limitation of SQL Server: the SQL Server transaction log doesn’t store information about who performed operations.
User information can be shown only for transactions that occur in open session(s). Backups do not contain such information and that's why we display SPID information only.
The fields are present in the Log Reader because if the user/Session ID is still active we can go grab it live, but once it’s disconnected it’s no longer there for us to get.