In your System Settings there is a setting which allows you to enable or disable apps to automatically load when you startup your computer. If you have this app set to open at startup, then that would explain why it is presenting its login. To check if this is the case:
- Open System Settings.
- Click on General in the left window.
- Click on Login Items in the window that opens on the right.
- The next window that opens will display the items set for the login at startup process with enable/disable buttons.
If that is not the case, then I suggest the you contact Mostly directly for assistance.