Document Manager has wrong login name

Site with multiple machines running MYOB AE v2.4.8. They have MYOB Document Manager v5.4 running in System Tray. Noticed on one machine, the username shown for Document Manager is showing a different staff member to the one logged in (see image).

MYOB is logged in as the right user, have tried clicking on DM & selecting 'Login as', and that lets us log in as the correct user, but it still shows as the other staff member. Doesn't seem to be causing any actual issues in MYOB, but want to correct it to prevent any logging & security issues.