Hello Steve,
I haven't used this. But can you try with the below option as per the note, I guess you need to give ".*TEST.*"
1988592 - SFTP Adapter not picking files with *
Cause
The syntax to include placeholders in the file name field on the SFTP adapter is different from the syntax used on the File adapter.
Resolution
In order to work with placeholders on the file name parameter the value needs to be separated by a dot ".", such as "test.*.xml" instead of "test*.xml".
Placeholders are supported on the SFTP adapter since the correct syntax is used.
Not sure if it helps, give a try!