I am experiencing a very weird problem with my UFX.

I have my Motif ES connected to the MIDI 1 I/O in the back of the unit. Midi In and Midi Out.
When I have the computer on everything works fine, I can send midi date from Motif to Cubase and from Cubase to Motif correctly. Motif is connected to UFX analog inputs and setup in total mix so their channels are audible.

When I turn off the PC and run the UFX in standalone mode I get notes generated when I press some certain notes in the low down octave, especially on big velocities.

For example, when I play a C0 and hold the pedal, the note gets triggered again 1-2seconds later and it is held forever.
This made me think that something is wrong so I tried:

To turn off the UFX and turn it back on
To turn off Motif and turn it back on in case something was messed up with the midi

Last thing I did was disconnecting the Midi Out cable from UFX. This solved the problem. After reconnecting it I was getting again the low notes. So UFX obviously sends some midi data to the Midi Out port when in Standalone mode.

I searched the forum and found a user with a FF800 having a similar issue.

I use :

RME UFX drivers 0.984, latest firmware 138
Windows 7 64bit Ultimate (although this is somewhat irrelevant as the problem happens only in standalone mode).