Strange MIDI problem with Virus B

[QuadraF]

I signed up here last night with a feeling of dread as my Virus behaving really strange, in the back of my mind i was thinking i'd bought a damaged unit.

Basically it was changing random parameters when i turned a knob on the virus.
Say i simply turned the filter cutoff control it would suddenly add loads of lfo mod matrix desinations, change patch vol, random amp and filter env settings.

I since tried it on a different MIDI port (previous one was RME Fireface MIDI 2) and it seems ok now. So im very happy the Virus is not broken.

But now im wondering what was causing this.. was my sequencer sending some strange midi control signals?
Is there something wrong with the Fireface?

Has this happened to anyone else here?
Or is there anyone with a better understanding of MIDI who can explain what was happening?

Any replies will be a massive help