Is the timestamp on openlisters.oll recent?
If not, something may be preventing Opus from updating the file.
If it is recent then I think there may be some misunderstanding about exiting Opus and what the "open the listers that were open when the program was last closed" option does. By default, simply closing all of open Opus windows will not cause Opus to exit; it will stay running in the background unless configured not to. It's only when it actually exits that the current window state is stored, and only after exit that the startup settings will have any effect. If you are closing all Opus windows and then exiting Opus (e.g. by rebooting the computer), then openlisters.oll will record that no windows were open when Opus was exited. See here for more info.