Thanks for your letting us know about this issue. The standard way to set a predetermined path using the plugin would be in the Event Page's Autonomous Movement box to set Custom type Movement and then create the Move Route there using the command list. If this Event does not use the <TBM Free Move> tag, then ensure that 'Skip If Cannot Move' box in the Move Route is unchecked to avoid any potential issues. Other possible sources of this issue could be with Event frequency (which you've already made sure to set to 5) and Tile passability (which likely isn't the case as you have checked that the route is working when the plugin is not on).
If you can provide screenshots of your plugin order and how you have set up the FOE event, then we may be able to help you troubleshoot this further. You can take a screenshot of the debugger (pressing F8) while running the game and you are testing this FOE. If you see any error messages it means that there is a code-level bug that is causing the plugin to not work as intended and it would also tell us where in the code that issue is happening. Either way, we are happy to help and make sure the plugin is doing its job properly :)