The signal should either be grounded or at 5V, if you leave it disconnected it will float and it sounds like it happens to float above 5V. If you wired the DO to the DI it should work as expected, where it will either be 5V or grounded and not floating.
Does your installation package the various plugins? This may help if the installation were to update all the components. This does bring up an interesting issue though of how you can manage updates to the plugins. Have you considered using JKI's Package Manager?